During the brief life of the Stars Our Destination Project, a total of fifteen individuals were granted ownership of seventeen stars. Other than Cheng Xin, the other fourteen owners were lost to history, and no legal heirs could be located. The Great Ravine acted like a giant sieve, and too many did not make it through. Now, Cheng Xin was the only one who held legal title to a star.

Cheng Xin gazed up at her star from the top of a giant tree. It was why she had been awakened.

Though humanity still hadn't begun to reach for any star beyond the Solar System, the rapid pace of technological progress meant that stars within three hundred light-years of the Earth were no longer of mere symbolic value. DX3906, Cheng Xin's star, turned out to have planets after all. Of the two planets discovered so far, one seemed very similar to Earth based on its mass, orbit, and a spectrum analysis of its atmosphere. As a result, its value rose to stratospheric heights. To everyone's surprise, they discovered that this star already had an owner.

The UN and the Solar System Fleet wanted to reclaim DX3906, but this couldn't be done legally unless the owner agreed to transfer the title. Thus Cheng Xin was awakened from her slumber after 264 years of hibernation.

The first thing she found out after emerging from hibernation was this: As she had expected, there was no news whatsoever about the Staircase Program. The Trisolarans had not intercepted the probe, and they had no idea of its whereabouts. The Staircase Program had been forgotten by history, and Tianming's brain was lost in the vastness of space. But this man, this man who had merged into nothingness, had left a real, solid world for his beloved, a world composed of a star and two planets.

A Ph. D. in astronomy named AA had discovered the planets around DX3906. As part of her dissertation, AA had developed a new technique that used one star as a gravitational lens through which to observe another.

To Cheng Xin, AA resembled a vivacious bird fluttering around her nonstop. AA told Cheng Xin that she was familiar with people like her, who had come from the past -- known as "Common Era people" after the old calendar -- since her own dissertation advisor was a physicist from back then. Her knowledge of Common Era people was why she had been appointed as Cheng Xin's liaison from the UN Space Development Agency as her first job after her doctorate.

The request from the UN and the fleet to sell the star back to them put Cheng Xin in an awkward position. She felt guilty possessing a whole world, but the idea of selling a gift that had been given to her out of pure love made her ill. She suggested that she could give up all claim of ownership over DX3906 and keep the deed only as a memento, but she was told that was unacceptable. By law, the authorities could not accept such valuable real estate without compensating the original owner, so they insisted on buying it. Cheng Xin refused.

AA told Cheng Xin that since she was only selling the planets, the amount of compensation offered by the UN was much lower. But it was still an astronomical sum, and she would need to form a company to manage it properly.

After much reflection, she came up with a new proposal: She would sell the two planets, but retain ownership of the star. At the same time, she would sign a covenant with the UN and the fleet granting humanity the right to use the energy produced by the star. The legal experts eventually concluded that this proposal was acceptable.

"Would you like me to help you run this company?" AA asked.

Cheng Xin agreed, and AA immediately called the UN Space Development Agency to resign. "I'm working for you now," she said, "so let me speak for a minute about your interests."

"Are you nuts?! Of all the choices available to you, you picked the worst! You could have sold the star along with the planets, and you would have become one of the richest people in the universe! Alternatively, you could have refused to sell, and kept the entire solar system for yourself. The law's protection of private property is absolute, and no one could have taken it away from you. And then you could have entered hibernation and woken up only when it's possible to fly to DX3906. Then you could go there! All that space! The ocean, the continents… you can do whatever you want, of course, but you should take me with you --"

"I've already made my decision," Cheng Xin said. "There's almost three centuries separating us. I don't expect us to understand each other right away."

Even with the glow from the lights of the city below, Cheng Xin easily found DX3906. Compared to the twenty-first century, the air was far clearer. She turned from the night sky to the reality around her: She and AA stood like two ants on top of a glowing Christmas tree, and all around them stood a forest of Christmas trees. Buildings full of lights hung from branches like leaves. But this giant city was built on top of the earth, not below it. Thanks to the peace of the Deterrence Era, humanity's second cave-dwelling phase had come to an end.

"Fine." AA sighed. "But you should reevaluate your conception of duty and conscience. Duty drove you to give up the planets, and conscience made you keep the star, but duty again made you give up the star's energy output. You're one of those people from the past, like my dissertation advisor, torn by conflict between two ideals. But, in our age, conscience and duty are not ideals: an excess of either is seen as a mental illness called social-pressure personality disorder. You should seek treatment."

They walked along the bough toward the tip. Each branch of the tree was a busy avenue full of floating translucent windows filled with information. They made the street look like a varicolored river. From time to time, a window or two left the traffic in the road and followed them for a while, and drifted back into the current when AA and Cheng Xin showed no interest. All the buildings on this branch-street hung below. Since this was the highest branch, the starry sky was right above them. If they had been walking along one of the lower branches, they would be surrounded by the bright buildings hanging from the branch above, and they would have felt like tiny insects flying through a dream forest, in which every leaf and fruit sparkled and dazzled.

Cheng Xin looked at the pedestrians along the street: a woman, two women, a group of women, another woman, three women -- all of them were women, all beautiful. Dressed in pretty, luminous clothes, they seemed like the nymphs of this magical forest. Once in a while, they passed some older individuals, also women, their beauty undiminished by age. As they reached the end of the branch and surveyed the sea of lights below them, Cheng Xin asked the question that had been puzzling her for days. "What happened to the men?" In the few days since she had been awakened, she had not seen a single man.

Cheng Xin stared. The individuals AA indicated had smooth, lovely faces; long hair that draped over their shoulders; slender, soft bodies -- as if their bones were made of bananas. Their movements were graceful and gentle, and their voices, carried to her by the breeze, were sweet and tender… Back in her century, these people would have been considered ultra-feminine.

"What do you mean? They're everywhere." AA pointed at the people around them. "Over there: See the man leaning against the balustrade? And there are three over there. And two walking toward us."

Understanding dawned on her after a moment. The trend had been obvious even earlier. The decade of the 1980s was probably the last time when masculinity, as traditionally defined, was considered an ideal. After that, society and fashion preferred men who displayed traditionally feminine qualities. She recalled the Asian male pop stars of her own time who she had thought looked like pretty girls at first glance. The Great Ravine interrupted this tendency in the evolution of human society, but half a century of peace and ease brought about by the Deterrence Era accelerated the trend.

"You're thinking of him again, aren't you?" AA grabbed her by the shoulders. "Even if he hadn't gone into space and had spent the rest of his life with you, the grandchildren of your grandchildren would be dead by now. This is a new age; a new life. Forget about the past!"

Close to three centuries ago, when Cheng Xin had been preparing for hibernation, she had imagined all kinds of difficulties she would face in the future, but this was something she was unprepared for. She imagined what it would be like to live the rest of her life in this feminine world… and her mood turned melancholic. She looked up and searched for her star.

"It's true that Common Era people usually have trouble telling men and women apart at first," AA said. "But I'll teach you a trick. Pay attention to the way they look at you. A classical beauty like you is very attractive to them."

Cheng Xin looked at her, a bit flustered. "No, no!" AA laughed. "I really am a woman, and I don't like you that way. But, honestly, I can't see what's attractive about the men of your era. Rude, savage, dirty -- it's like they hadn't fully evolved. You'll adjust to and enjoy this age of beauty."

Cheng Xin thought the man's face looked familiar, but before she could look more closely, the image had disappeared. In his place appeared a middle-aged woman -- well, at least Cheng Xin thought she was a woman. Wearing formal, non-glowing clothes that reminded Cheng Xin of a politician's, she was in the middle of giving a speech. The text earlier had been a part of the subtitles for her speech.

A thought popped into her mind. A world dedicated to femininity… but what does that mean for deterrence?

Cheng Xin tried to think as AA suggested and forced herself to return to the present. She had only been here for a few days, and had just grasped the broadest outline of the history of the past three centuries. The strategic balance between the humans and the Trisolarans as a result of dark forest deterrence had shocked her the most.

Cheng Xin and AA walked back along the bough. Again, a few informational windows drifted along with them, and this time, one drew Cheng Xin's attention. The window showed a man, clearly a man from the past: haggard, gaunt, messy hair, standing next to a black tombstone. The man and the tombstone were in shadows, but his eyes seemed to glow brightly with the reflected light of a distant dawn. A line of text appeared on the bottom of the screen:

Back during his time, a killer would be sentenced to death.

"Another correct answer would be: because he killed too few. Killing one person was murder; killing a few or dozens was more murder; so killing thousands or tens of thousands ought to be punished by putting the murderer to death a thousand times. What about more than that? A few hundred thousand? The death penalty, right? Yet, those of you who know some history are starting to hesitate.

The window seemed to notice Cheng Xin's interest. It expanded and began to play the audio accompanying the video. The politician's voice was lovely and sweet, as though the words were strung together by strands of blown sugar. But the content of the speech was terrifying.

"Why the death penalty? Answer: because he killed. But that is only one correct answer.

"What if he killed millions? I can guarantee you such a person would not be considered a murderer. Indeed, such a person may not even be thought to have broken any law. If you don't believe me, just study history! Anyone who has killed millions is deemed a 'great' man, a hero.

"Why?"

"They're talking about Luo Ji," said AA. "They want to put him on trial."

"And if that person destroyed a whole world and killed every life on it -- he would be hailed as a savior!"

"Hey, you must be Cheng Xin!"

"You're the woman who owns that faraway world! Like a ray of hope, you've brought the beauty of your time to us. As the only human being ever to possess an entire world, you will also save this world. All of us have faith in you. Oh, sorry, I should introduce myself --"

"It's complicated. But basically, it's because of that world, the world whose location he broadcast to the universe, causing it to be destroyed. We don't know if there was life on that world -- it's a possibility. So they're charging him with suspected mundicide, the most serious crime under our laws."

AA kicked the window and shut it off. Cheng Xin was utterly amazed by the technology level of this age. She had no idea how her own image had been transmitted to the speaker, and no idea how the speaker was then able to pick her out of the billions who were watching her speech.

The voice shocked Cheng Xin. It had come from the floating window in front of her. The politician in it gazed at Cheng Xin, joy and surprise on her face, as though she were seeing an old friend.

"This is a meaningless question. I would never put myself in that position."

AA rushed in front of Cheng Xin and walked backwards as they talked. "Would you have destroyed a world to create this form of deterrence? And, more importantly, if the enemy weren't deterred, would you press the button to ensure the destruction of two worlds?"

AA stopped and grabbed Cheng Xin by the shoulders. She stared into her eyes. "Really? You wouldn't?"

The next morning, Cheng Xin got a call from AA.

"Of course not. Being put in such a position is the most terrifying fate I can think of. Far worse than death."

AA showed up on the screen looking excited. "I'm going to surprise you and take you somewhere cool. Come on up. The car is at the top of the tree."

Cheng Xin went up and saw a flying car with its door open. She got in but didn't see AA. The door slid shut noiselessly and the seat molded itself around her, holding her tight like a hand. Gently, the car took off, merging into the streaming traffic of the forest-city.

She couldn't understand why AA seemed so earnest, but AA nodded. "That puts me at ease… Why don't we talk more tomorrow? You're tired and should get more rest. It takes a week to completely recover from hibernation."

Half an hour later, the car landed and the door slid open automatically. Cheng Xin got out, and the car rose into the air and left. After the turbulence from the propellers subsided, silence reigned over everything, pierced by occasional birdsong from far away. Cheng Xin looked around and found herself in the midst of a group of abandoned buildings. They looked like residential buildings from the Common Era. The bottom half of every building was covered in ivy.

After the start of the Deterrence Era, most heavy industries had moved into orbit, and the Earth's natural ecology recovered. The surface of the Earth now looked more like it did in pre-Industrial Revolution times. Due to a drop in population and further industrialization of food production, much of the arable land was allowed to lie fallow and return to nature. The Earth was transforming into a giant park.

It was still early, and shafts of sunlight, almost parallel to the ground, flickered through the car as it passed through the forest. Gradually, the giant trees thinned out and, finally, disappeared. Under the blue sky, Cheng Xin saw only grassland and woodland, an intoxicating green mosaic.

This beautiful world seemed unreal to Cheng Xin. Though awakened from hibernation, she felt as though she were in a dream.

She turned and saw a man standing on an ivy-covered second-story balcony. He wasn't like the soft, beautiful men of this time, but like the men of the past. Cheng Xin seemed to be dreaming again, a continuation of her nightmare from the Common Era.

The sight of the past covered by the green life of a new era gave Cheng Xin the sense of reality that she had been missing.

She called for AA, but a man's voice responded. "Hello."

Cheng Xin's eyes were focused on Wade's right hand. The hand, covered by a black leather glove, held an old Common-Era gun that was pointing at Cheng Xin.

It was Thomas Wade. He wore a black leather jacket, but he looked a bit older. Perhaps he had gone into hibernation after Cheng Xin, or perhaps he had awakened before her, or both.

"The bullet in here was designed to be shot underwater," said Wade. "It's supposed to last a long time. But it's been more than two hundred and seventy years. Who knows if it will work?" That familiar smile, the one he wore when he was taking delight in the despair of others, appeared on his face.

"Why?" Cheng Xin didn't feel pain. Her left shoulder felt numb, as if it didn't belong to her.

"Did you kill Vadimov?" she asked. Blood seeped from the corner of her mouth.

A flash. An explosion. Cheng Xin felt a hard punch against her left shoulder and the force slammed her against the broken wall behind her. The thick ivy muffled much of the noise from the gunshot. Distant birds continued to chitter.

"I want to be the Swordholder. You are my competitor, and you're going to win. I don't harbor any ill will toward you. Whether you believe me or not, I feel terrible at this moment."

"Yes. The Staircase Program needed him. And now, my new plan does not need you. Both of you are very good, but you're in the way. I have to advance, advance without regard for consequences."

Another shot. The bullet went through the left side of Cheng Xin's abdomen. She still didn't feel pain, but the spreading numbness made her unable to keep standing. She slid down against the wall, leaving a bright trail of blood on the ivy behind her.

"I can't use a modern gun," said Wade. "Every shot is automatically recorded in the public security databases now." His tone was as serene as it had been when he used to discuss routine tasks with her.

Wade pulled the trigger again. Finally, the passage of nearly three centuries caught up with the gun, and it made no sound. Wade racked the slide to clear the dud out of the chamber. Once again, he pointed the gun at Cheng Xin.

His right arm exploded. A puff of white smoke rose into the air, and Wade's right forearm was gone. Burnt bits of bone and flesh splattered into the green leaves around him, but the gun, undamaged, fell to the foot of the building. Wade didn't move. He took a look at the stump of his right arm and then looked up. A police car was diving toward him.

As the police car approached the ground, several armed police officers jumped out and landed in the thick grass waving in the turbulence thrown up by the propellers. They looked like slender, nimble women.

A fierce wave of pain seized her, and she lost consciousness.

The last one to jump out of the car was AA. Cheng Xin's vision was blurring, but she could see AA's tearful face and hear her sobbing explanation.

"… faked my call…"

When Cheng Xin woke up, she found herself in a flying car. A film clung to her and wrapped her tightly. She couldn't feel pain, couldn't even feel the presence of her body. Her consciousness began to fade again. In a faint voice that no one but herself could hear, she asked, "What is a Swordholder?"

The main elements of deterrence are these: the deterrer and the deteree (in dark forest deterrence, humanity and Trisolaris); the threat (broadcasting the location of Trisolaris so as to ensure the destruction of both worlds); the controller (the person or organization holding the broadcast switch); and the goal (forcing Trisolaris to abandon its invasion plan and to share technology with humanity).

[Excerpt from A Past Outside of Time, The Ghost of the Wallfacers: The Swordholder]

Without a doubt, Luo Ji's creation of dark forest deterrence against Trisolaris was a great achievement, but the Wallfacer Project that led to it was judged a ridiculous, childish act. Humanity, like a child entering society for the first time, had lashed out at the sinister universe with terror and confusion. Once Luo Ji had transferred control of the deterrence system to the UN and the Solar System Fleet, everyone thought the Wallfacer Project, a legendary bit of history, was over.

People turned their attention to deterrence itself, and a new field of study was born: deterrence game theory.

Thus, the key to the success of ultimate deterrence is the belief by the deteree that the threat will almost certainly be carried out if the deteree thwarts the deterrer's goals. This probability, or degree of deterrence, is an important parameter in deterrence game theory. The degree of deterrence must exceed 80 percent for the deterrer to succeed.

But people soon discovered a discouraging fact: If the authority to carry out the threat in dark forest deterrence is held by humanity as a whole, then the degree of deterrence is close to zero.

Compared to other types of deterrence, ultimate deterrence is distinguished by the fact that, should deterrence fail, carrying out the threat would be of no benefit to the deterrer.

When the deterrent is the complete destruction of both the deterrer and the deteree, the system is said to be in a state of ultimate deterrence.

Asking humanity to take an action that would destroy two worlds is difficult: The decision would violate deeply held moral principles and values. The particular conditions of dark forest deterrence made the task even harder. Should deterrence fail, humanity would survive for at least one more generation. In a sense, everyone alive would be unaffected. But in the event of deterrence failing, carrying out the threat and broadcasting would mean that destruction could come at any moment, a far worse result than not carrying out the threat. Thus, if deterrence failed, the reaction of humankind as a whole could be easily predicted.

The success of dark forest deterrence was founded on the unpredictability of Luo Ji as an individual. If deterrence failed, his actions would be guided by his own personality and psychology. Even if he acted rationally, his own interests might not match humanity's interests perfectly. At the beginning of the Deterrence Era, both worlds carefully analyzed Luo Ji's personality and built up detailed mathematical models. Human and Trisolaran deterrence game theorists reached remarkably similar conclusions: Depending on his mental state at the moment deterrence failed, Luo Ji's degree of deterrence hovered between 91.9 percent and 98.4 percent. Trisolaris would not gamble with such odds.

But an individual's reaction could not be predicted.

Of course, such careful analysis wasn't possible immediately after the creation of dark forest deterrence. But humanity quickly reached this conclusion intuitively, and the UN and the Solar System Fleet handed the authority to activate the deterrence system back to Luo Ji like a hot potato. The entire process from Luo Ji turning over the authority to getting it back took a total of eighteen hours. Yet that would have been long enough for droplets to destroy the ring of nuclear bombs surrounding the Sun and deprive humanity of the ability to broadcast their locations. The Trisolarans' failure to do so was widely considered their greatest strategic blunder during the war, and humanity, covered in cold sweat, let out a held breath.

Since then, the power to activate the dark forest deterrence system had always been vested in Luo Ji. His hand first held the detonation switch for the circumsolar ring of nuclear bombs, and then the switch for the gravitational wave broadcast.

The Wallfacer Project did not fade into history after all. Humanity could not escape the Wallfacers' ghost.

Although the Wallfacer Project was an unprecedented anomaly in the history of humankind, both dark forest deterrence and the Swordholder had precursors. The mutual assured destruction practiced by NATO and the Warsaw Pact during the Cold War was an example of ultimate deterrence. In 1974, The Soviet Union initiated the Perimeter System (Russian Система «Периметр»), or "Dead Hand." This was intended to guarantee that the Soviet Union possessed a viable second-strike capability in the event that an American-led first strike eliminated the Soviet government and high-level military command centers. The system relied on a monitoring system that gathered evidence of nuclear explosions within the Soviet Union; all the data was transmitted to a central computer that interpreted the data and decided whether to launch the Soviet Union's nuclear arsenal.

Dark forest deterrence hung over two worlds like the Sword of Damocles, and Luo Ji was the single hair from a horse's tail that held up the sword. Thus, he came to be called the Swordholder.

In 2009, an officer who had been on duty in the room decades earlier told a reporter that at the time, he was a twenty-five-year-old junior lieutenant, freshly graduated from Frunze Military Academy. If the system determined that a strike was necessary, he was the last check before the complete destruction of the world. At that moment, all of the Soviet Union and Eastern Europe would likely be a sea of flames, and all of his loved ones above ground almost certainly dead. If he pushed the button, North America would also turn into hell on Earth in half an hour, and the following nuclear winter would doom all of humanity. He would hold the fate of human civilization in his hand.

The first Swordholder in history answered: I don't know.

The heart of the system was a secret control chamber hidden deep underground. If the system determined that a counterstrike must be launched, an operator on duty would initiate it.

Later, he was asked this question many times: If that moment had really arrived, would you have pushed the button?

Time passed in this strange balance. Deterrence had been in effect for sixty years, and Luo Ji, who was now over a hundred, still held the switch to initiate the broadcast. His image among the populace had also gradually changed.

Humanity hoped that dark forest deterrence would have a happy ending, like the mutually assured destruction of the twentieth century.

Hawks who wished to take the hard line against Trisolaris did not like him. Near the beginning of the Deterrence Era, they advocated imposing more severe conditions on the Trisolarans, with the goal of completely disarming Trisolaris. Some of their proposals were absurd. For instance, one idea was the "naked resettlement" program, which would have demanded that all Trisolarans dehydrate and allow themselves to be transported by cargo ships to the Oort Cloud, where they would be picked up by human spaceships and brought to the Solar System to be stored in dehydratories on Mars or the moon. Thereafter, if the Trisolarans satisfied certain conditions, they would be rehydrated in small batches.

Luo Ji ignored them all. He held the switch to the gravitational wave broadcast system and silently stood at the Swordholder post for half a century.

Humanity came to realize that all policies with respect to the Trisolarans had to take the Swordholder into account. Without his approval, no human policy had any effect on Trisolaris. Thus, the Swordholder became a powerful dictator, much like the Wallfacers had.

The doves, similarly, did not like Luo Ji. Their primary concern was whether the star 187J3X1, whose location had been broadcast by Luo Ji, had possessed planets that harbored life and civilization. No astronomer from the two worlds could definitively answer this question: It was impossible to prove the affirmative or the negative. But it was certain that Luo Ji could be suspected of having committed mundicide. The doves believed that in order for humanity and Trisolaris to peacefully coexist, the foundation must be universal "human" rights -- in other words, the recognition that all civilized beings in the universe had inviolable, fundamental rights. To make such an ideal into reality, Luo Ji must be tried.

As time passed, Luo Ji slowly came to be seen as an irrational monster and a mundicidal despot.

People realized that the Deterrence Era was a strange time. On the one hand, human society had reached unprecedented heights of civilization: Human rights and democracy reigned supreme everywhere. On the other hand, the entire system existed within the shadow of a dictator. Experts believed that although science and technology usually contributed to the elimination of totalitarianism, when crises threatened the existence of civilization, science and technology could also give birth to new totalitarianism. In traditional totalitarian states, the dictator could only enact his control through other people, which led to low efficiency and uncertainty. Thus, there had never been a 100 percent effective totalitarian society in human history. But technology provided the possibility for such a super-totalitarianism, and both the Wallfacers and the Swordholder were concerning examples. The combination of supertechnology and a supercrisis could throw humankind back into the dark ages.

There was one more choice: turning over control of the deterrence system to artificial intelligence. This was a choice that had been evaluated seriously, and much effort was expended in researching its feasibility. Its biggest advantage was a very high degree of deterrence. But ultimately, it wasn't adopted. Handing over the fate of two worlds to machines was a terrifying idea. Experiments showed that AIs tended not to make correct decisions when faced with the complex conditions of deterrence -- unsurprising, since correct judgment required more than logical reasoning. Moreover, changing from a dictatorship-by-man to a dictatorship-by-machine wouldn't have made people feel any better, and was politically worse. Finally, sophons could interfere with AI reasoning. Though no example of such interference had been discovered, the mere possibility made the choice inconceivable.

But most people also agreed that deterrence remained necessary. After the sophons unblocked the progress of human technology and the Trisolarans began transferring their knowledge to humans, human science had advanced by leaps and bounds. However, compared to Trisolaris, Earth was still behind by at least two or three technology ages. Decommissioning the deterrence system was to be considered only when the two worlds were approximately equal in technology.

A compromise was to change the Swordholder. Even without the above considerations, Luo Ji was a centenarian. His thinking and psychological state were becoming more unreliable, and people were growing uneasy that the fate of both worlds rested in his hands.

Cheng Xin's recovery proceeded apace. The doctors told her that even if all ten seven-millimeter bullets in the gun had struck her, and even if her heart had been shattered, modern medicine was capable of reviving her and fixing her up good as new -- though it would have been a different matter if her brain had been hit.

[Deterrence Era, Year 61, The Swordholder]

The police told her that the last murder case in the world had occurred twenty-eight years ago, and this city hadn't had a murder case in almost forty years. The police were out of practice when it came to the prevention and detection of murder, and that was why Wade had almost succeeded. Another candidate for the Swordholder position had warned the police. But Wade's competitor had presented no proof, only a suspicion of Wade's intent based on a sensitivity that this era lacked. The police, dubious of the accusation, wasted a lot of time. Only after discovering that Wade had faked a call from AA did they take action.

The world no longer seemed so strange, and Cheng Xin yearned to know it better, but she was stuck in her hospital room.

One day, AA came and played a holographic movie for her. The movie, named A Fairy Tale of Yangtze, had won Best Picture at that year's Oscars. It was based on a song composed in busuanzi verse form by the Song Dynasty poet Li Zhiyi:

I think of you each day, beloved, though we cannot meet.

Many people came to visit Cheng Xin at the hospital: officials from the government, the UN, and the Solar System Fleet; members of the public; and, of course, AA and her friends. By now, Cheng Xin could easily tell the sexes apart, and she was growing used to modern men's completely feminized appearance, perceiving in them an elegance that the men of her era lacked. Still, they were not attractive to her.

You live at one end of the Yangtze, and I the other.

We drink from the same river.

The film was set in some unspecified ancient golden age, and told the story of a pair of lovers, one who lived at the source of the Yangtze, and the other at its mouth. The pair was kept apart for the entire film; they never got to see each other, not even in an imaginary scene. But their love was portrayed with utter sorrow and pathos. The cinematography was also wonderful: The elegance and refinement of the lower Yangtze Delta and the vigor and strength of the Tibetan Plateau contrasted and complemented each other, forming an intoxicating mix for Cheng Xin.

The movie stimulated Cheng Xin's interest in the culture of her new era. Once she recovered enough to walk, AA brought her to art shows and concerts. Cheng Xin could clearly remember going to Factory 7984 and the Shanghai Biennale to see strange pieces of contemporary "art," and it was hard for her to imagine how much art had evolved in the three centuries she was asleep. But the paintings she saw at the art show were all realistic -- beautiful colors enlivened with vitality and feeling. She felt each painting was like a heart, beating gently between the beauty of nature and human nature. As for the music, she thought everything she heard sounded like classical symphonies, reminding her of the Yangtze in the movie: imposing and forceful, but also calm and soothing. She stared at the flowing river until it seemed that the water had ceased moving, and it was she that was moving toward the source, a long, long way…

The film lacked the heavy-handedness of the commercial films of her own era. Instead, the story flowed as naturally as the Yangtze itself, and absorbed Cheng Xin effortlessly.

I'm at one end of the River of Time, Cheng Xin thought, but the other end is now empty…

The art and culture of this age were nothing like what she had imagined, but it wasn't simply a matter of a return to classical style, either. It was more of a spiraling sublimation of post-postmodernism, built upon a new aesthetic foundation. For instance, A Fairy Tale of Yangtze contained profound metaphors for the universe and space and time. But Cheng Xin was most impressed by the disappearance of the gloomy despair and bizarre noise so prevalent in the postmodern culture and art of the twenty-first century. In their place was an unprecedented warm serenity and optimism.

"You'd be even more surprised if you knew the artists behind these films, paintings, and music. They're all Trisolarans from four light-years away." AA laughed uproariously as she observed Cheng Xin's stunned gape.

"I love your era," said Cheng Xin. "I'm surprised."

[Excerpt from A Past Outside of Time, Cultural Reflection]

After the creation of deterrence, the World Academy of Sciences -- an international organization at the same level as the UN -- was founded to receive and digest the scientific and technical information transmitted to Earth from Trisolaris.

There was so much knowledge, in fact, that it completely overwhelmed the scientific community on Earth. Trisolaris then provided ongoing guidance for the study and absorption of this knowledge. For a while, the whole world resembled a giant university. After the sophons ended their interference with the particle accelerators, Earth scientists were able to experimentally verify the core ideas of Trisolaran physics, giving humanity confidence in the veracity of these revelations. The Trisolarans even complained multiple times that humanity was absorbing the new knowledge too slowly. The aliens seemed eager for Earth to catch up to Trisolaris in scientific understanding -- at least in the basic sciences.

People first predicted that Trisolaris would only provide knowledge to Earth in sporadic, disconnected fragments after much pressure, and sprinkle deliberate falsehoods and misleading ideas into what little they chose to share, so the scientists of Earth would have to sift through them carefully for nuggets of truth. But Trisolaris defied those expectations. Within a brief period of time, they systematically transmitted an enormous amount of knowledge. The treasure trove mainly consisted of basic scientific information, including mathematics, physics, cosmology, molecular biology of Trisolaran life forms, and so on. Every subject was a complete system.

The Trisolarans explained their own actions this way: Their generous gift of knowledge was done out of respect for Earth civilization. They claimed that Trisolaris had received even more benefits from Earth. Human culture gave Trisolaris new eyes, allowed Trisolarans to see deeper meanings in life and civilization and appreciate the beauty of nature and human nature in ways they had not understood. Human culture was widely disseminated on Trisolaris, and was rapidly and profoundly transforming Trisolaran society, leading to multiple revolutions in half a century and changing the social structure and political system on Trisolaris to be more similar to Earth's. Human values were accepted and respected in that distant world, and all Trisolarans were in love with human culture.

Faced with such a puzzling response, humans came up with multiple explanations. The most plausible theory posited that the Trisolarans understood the advantage of the accelerating pace of human scientific development and wanted to gain access to new knowledge through us. Earth was treated as a knowledge battery: After it was charged fully with Trisolaran knowledge, it would provide more power.

These days, without being explicitly told, it was very hard to tell if a film or novel was authored by a human or a Trisolaran. The characters in Trisolaran artistic creations were all human, and they were set on Earth, with no trace of alienness. This seemed a powerful confirmation of the acceptance of Earth culture by Trisolaris. At the same time, Trisolaris itself remained shrouded in mystery, with almost no details about the world itself being transmitted. The Trisolarans explained this by saying that their own crude native culture was not ready to be shown to humans. Given the vast gap in biology and natural environment between the two worlds, such displays might erect unexpected barriers in the valuable exchange that was already taking place.

After the tenth year of the Deterrence Era, besides additional scientific information, Trisolaris began to transmit cultural and artistic products done in imitation of human models: films, novels, poetry, music, paintings, and so on. Surprisingly, the imitations were not at all awkward or childish; right away, the Trisolarans produced sophisticated, high-quality art. Scholars called this phenomenon cultural reflection. Human civilization now possessed a mirror in the universe, through which humanity gained a new understanding of itself through a novel perspective. In the following ten years, Trisolaran reflection culture became popular on Earth, and began to displace the decadent native human culture that had lost its vitality. Reflection culture became the new source for scholars seeking new cultural and aesthetic ideas.

At the beginning, humans were skeptical of these claims, but the incredible wave of cultural reflection that followed seemed to prove them true.

[Deterrence Era, Year 61, The Swordholder]

Humanity was glad to see everything developing in a positive direction. A ray of sunlight lit up this corner of the dark forest.

Sophon lived on a giant tree at the edge of the city. Viewed from the flying car, the leaves on the tree were sparse, as though it were late autumn. Sophon lived on the branch at the top, where a single leaf hung, an elegant dwelling made of bamboo and surrounded by a white cloud. The day was cloudless, and it was clear that Sophon's house generated the white mist.

On the day of Cheng Xin's discharge, AA told her that Sophon wanted to meet her.

Cheng Xin understood that AA wasn't referring to the subatomic particles endowed with intelligence sent by Trisolaris, but to a woman, a robot woman developed by the most advanced human AI and bionics technology. She was controlled by the sophons and acted as the Trisolaran ambassador to Earth. Her appearance facilitated a more natural interchange between the two worlds than having sophons manifest themselves by unfolding in lower dimensions.

"Welcome, welcome! I wanted to pay a visit to your honored abode, but then I wouldn't be able to properly entertain you with the Way of Tea. Please accept my humble apologies. I am so delighted to see you." Sophon bowed again. Her voice was as gentle and soft as her body, barely audible, but it possessed an irresistible charm, as if all other voices had to pause and step aside when she spoke.

Cheng Xin and AA walked along the branch until they reached the tip. The road was lined with smooth pebbles, and they saw lush lawns on both sides. They descended a spiraling staircase to reach the door of the house itself, where Sophon welcomed them. The gorgeous Japanese kimono on her petite figure resembled a layer of blooming flowers, but when Cheng Xin saw her face, the flowers seemed to lose color. Cheng Xin could not imagine a more perfect beauty, a beauty animated by a lively soul. She smiled, and it was as though a breeze stirred a pond in spring and the gentle sunlight broke into a thousand softly undulating fragments. Slowly, Sophon bowed to them, and Cheng Xin felt her entire figure illustrated the Chinese character 柔, or soft, in both shape and meaning.

Bamboo groves lined both sides of the trail through the yard. A white fog hung among the bamboo, which reached about waist-high and undulated. They crossed a little wooden bridge over a trickling spring, and Sophon stepped to the side, bowed, and showed them into the parlor. The parlor was decorated in a pure Eastern style, full of sunlight and wide openings in the four walls so that the space resembled a pavilion. They could see the blue sky and white clouds outside. The clouds were generated by the house itself and dissipated into tendrils. A small ukiyo-e Japanese woodblock print hung on the wall, along with a fan decorated with a Chinese-brush-painting landscape. The whole place exuded an air of simple elegance.

The pair followed Sophon into the yard. The tiny white flowers in her bun quivered, and she turned around to smile at them from time to time. Cheng Xin had completely forgotten that she was an alien invader, that she was controlled by a powerful world four light-years away. All she saw was a lovely woman, distinguished by her overwhelming femininity, like a concentrated pigment pellet that could turn a whole lake pink.

Sophon waited until Cheng Xin and AA were sitting cross-legged on the tatami mats, then sat herself down gracefully. Methodically, she laid out the implements for the tea ceremony in front of her.

Sophon retrieved a spotless white cloth from her kimono and began wiping the equally spotless implements. First, she carefully, slowly wiped each and every tea scoop, delicate spoons with long handles carved from single pieces of bamboo. Then she wiped each and every white porcelain and yellow copper tea bowl. With a bamboo ladle, she transferred the clear spring water from a ceramic container to a teapot and placed it above a refined copper brazier to boil. Then she scooped powdered green tea from the tea caddy into the tea bowls, brushing them with a bamboo tea whisk in a circular motion…

"You're going to have to be patient," AA whispered in Cheng Xin's ear. "It'll be two hours before you get to drink any tea."

She performed each step in a deliberate, slow manner, even repeating some of the steps. Just wiping the tea ceremony implements took nearly twenty minutes. Clearly, Sophon executed these actions not for their results, but for their ceremonial significance.

After an unknown amount of time, the tea was ready. Following another series of complicated ceremonial procedures, Sophon finally handed the bowls of tea to Cheng Xin and AA. Cheng Xin took a sip of the lush, green drink. A fragrant, bitter sensation suffused her body, and her mind seemed to clear.

But Cheng Xin didn't feel bored. Sophon's graceful, gentle movements had a hypnotic, mesmerizing effect on her. From time to time, a light breeze wafted through the room, and Sophon's pale arms seemed to move not of their own accord, but to drift with the breeze. Her hands, smooth as jade, seemed to be caressing not implements for making tea, but something softer, lighter, more cloudlike… like time. Yes, she was caressing time. Time turned malleable and meandered slowly, like the fog that drifted through the bamboo groves. This was another time. Here, the history of blood and fire had disappeared, and the world of everyday concerns retreated somewhere far away. All that was left were clouds, the bamboo grove, and the fragrance of tea. They had achieved wa kei sei jaku -- harmony, respect, purity, and tranquility, the four principles of the Way of Tea.

Cheng Xin understood very well what was meant but not said, as well as the true significance of the tea ceremony.

The day after Cheng Xin visited Sophon, six Common Era men came to see her. These were the candidates competing to succeed Luo Ji in the Swordholder position. They were between thirty-four and sixty-eight years old. Compared to the beginning of the Deterrence Era, fewer Common Era individuals were emerging from hibernation, but they still formed a stratum of society on their own. All of them had some difficulty reintegrating into modern society. Most men from the Common Era tried to, consciously or otherwise, feminize their appearance and personality to adjust to the new feminine society. But the six men in front of Cheng Xin all stubbornly held on to their outdated masculine appearance and personality. If Cheng Xin had met them a few days ago, she would have found them comforting, but now, she felt only a sense of oppression.

"When all of us women are together, the world is so beautiful." Sophon's voice was still slow and mild, barely audible. "But our world is also very fragile. All of us women must take care to protect it." Then she bowed deeply, and her voice grew excited. "Thank you for your care in advance! Thank you!"

The next meeting pulled Cheng Xin back into the complex reality around her.

Cheng Xin first thanked the candidate who had warned the police. In this she was sincere -- he had saved her life, after all. The forty-eight-year-old man was named Bi Yunfeng, and he had once been a designer for the world's largest particle collider. Like Cheng Xin, he was sent as a liaison to the future in the hope that the particle collider would be restarted once humankind broke through the lock placed on them by the sophons. Unfortunately, none of the particle accelerators built during his time had survived to the Deterrence Era.

"I hope I haven't made a mistake," he said. Perhaps he was trying to be funny, but Cheng Xin and the others didn't laugh.

"We're here to persuade you to not compete for the Swordholder position." Another man got right to the point. His name was Cao Bin, and he was thirty-four, the youngest of the candidates. At the start of the Trisolar Crisis, he had been a physicist, a colleague of the famous Ding Yi. After the truth of the sophons' lock on fundamental research was revealed, he was disappointed by the thought that physics had turned into a mathematical game divorced from experimental basis, and entered hibernation to wait for the lock to be released.

She could see no sunlight in their eyes; their expressions appeared as masks that disguised their true feelings. Cheng Xin felt that she was facing a city wall built from six cold, hard rocks. The wall, roughened and toughened by the passing years, chilled her with its heaviness, and seemed to hint at death and bloodshed.

"If I do declare my candidacy, do you think I will win?" asked Cheng Xin. She had been pondering this question nonstop since her return from Sophon's home. She could barely sleep.

"If you do, it's almost certain that you will win," Ivan Antonov said. The handsome Russian was the next youngest of the candidates, at forty-three years old. He had an impressive résumé: Once the youngest vice-admiral in the Russian Navy, he later became the deputy commander of the Baltic Fleet. He had entered hibernation because of a terminal illness.

"Do I possess a lot of deterrent force?" asked Cheng Xin, smiling.

"You are not without qualifications. You once served in the PIA. During the last few centuries, that agency has actively gathered an enormous amount of intelligence about Trisolaris. Before the Doomsday Battle, it had even warned the human fleets about the imminent droplet attack, though the warning was ignored. Nowadays, the PIA is seen as a legendary organization, and this will give you points. In addition, you're the only human to possess another world, which makes you able to save this world… Never mind that the leap in logic is suspect; that's how the public thinks --"

"Let me get to the point," a bald man interrupted Antonov. He was named A. J. Hopkins -- or at least that's what he called himself. His identity had been completely lost by the time he emerged from hibernation, and he refused to divulge any information about himself, not even bothering to make it up. This made it difficult for him to become a citizen of the new world -- though his mysterious past also helped make him a competitive candidate. He and Antonov were considered to possess the most deterrent force. "In the eyes of the public, the ideal Swordholder looks like this: He should terrify the Trisolarans without terrifying the people of Earth. Since such a combination cannot exist, the people will lean toward someone who doesn't terrify them. You don't frighten them because you're a woman, and a woman who seems angelic in their eyes, at that. These sissies are more naïve than even the children of our time; all they can see are superficial qualities… Look, they all think everything is developing wonderfully, and we are on the cusp of achieving universal peace and love. Deterrence is no longer so important, so they want someone with a gentler hand holding the sword."

This last speech silenced Cheng Xin. She had just learned what Luo Ji had endured during the Deterrence Era.

The last candidate, an experienced attorney, now spoke up. "I don't think you really want to be the Swordholder. You must know what kind of sacrifices are required."

The six men didn't answer her, but they exchanged glances with each other. Their gazes now looked even darker and colder. Standing in their midst, Cheng Xin felt as if she were on the bottom of a well. She shivered.

"Isn't it true, though?" Cheng Xin asked. Hopkins's contemptuous tone annoyed her.

"Child, you're not suited to be the Swordholder." At sixty-eight, the speaker was the oldest of the candidates. Before hibernation, he had been South Korea's vice minister of foreign affairs. "You have no political experience, you are young, you lack the judgment to evaluate situations correctly, and you don't possess the requisite psychological qualities to be the Swordholder. All you have is kindness and a sense of responsibility."

After the six candidates departed, AA said to Cheng Xin, "I don't think what the Swordholder goes through can be called living. It's worse than being in hell. Why would these Common Era men want that?"

"Um, are you obsessed, too?"

"To be able to determine the fate of all of humanity and another race with a single finger is very attractive to some men from that era. Some devote their entire lives to pursue such power. They become obsessed with it."

Cheng Xin said nothing. Things were no longer simple.

"He's not the most dangerous."

"It's hard to imagine a man so dark, so crazy, so perverted." AA meant Wade.

This was true. Wade did not hide his viciousness deeply. The layers and layers of disguises that people of the Common Era wore to hide their real intentions and feelings were unimaginable to AA and contemporary humans. Who knew what was hidden behind the cold, expressionless masks worn by the six men? Who knew whether one of them might be another Ye Wenjie or Zhang Beihai? More terrifyingly, whether all of them were?

The beautiful world revealed its fragility to Cheng Xin, like a lovely soap bubble floating through a bramble bush: A single touch was enough to destroy everything.

A week later, Cheng Xin came to the UN Headquarters to attend the handover ceremony for the two planets in the DX3906 system.

But Cheng Xin could prevent all of this.

Afterwards, the PDC chair spoke with her. On behalf of the UN and the Solar System Fleet, he asked her to declare her candidacy for the Swordholder. He explained that there was uncertainty about the six existing candidates. For any of them to be elected would lead to mass panic, as a considerable portion of the population believed each of the candidates to be a tremendous danger and threat. The consequences of electing any of them were unpredictable. In addition, all of the candidates distrusted Trisolaris and exhibited aggressive tendencies toward it. If one of them were elected, the second Swordholder might collaborate with the hardliners on Earth and in Fleet International to impose harsher policies toward Trisolaris and demand more concessions from them. Such a move might terminate the developing peace and scientific and cultural exchange between the two worlds, leading to disaster…

After humanity ended its second cave-dwelling stage, the UN Headquarters moved back to its old address. Cheng Xin was familiar with it: The exterior of the Secretariat Building looked the same as three centuries ago, and even the sculptures on the plaza in front were perfectly preserved, as was the lawn. Cheng Xin stood and recalled that tumultuous night 270 years ago: the announcement of the Wallfacer Project; Luo Ji's shooting; the chaotic crowd under the swaying spotlights; her hair blowing about in the turbulence from the helicopters; the ambulance departing with flashing red lights and shrill sirens… everything was as clear as yesterday. Wade stood with his back against the lights of New York City, and uttered the line that had transformed her life: "We'll send only a brain."

"Look, she's like Saint Mary, the mother of Jesus!" the young mother called out to the crowd. She turned back to Cheng Xin and put her hands together. Tears flowed from her eyes. "Oh, beautiful, kind Madonna, protect this world! Do not let those bloodthirsty and savage men destroy all the beauty here."

Without that statement, everything that was happening now would have nothing to do with her. She would be a common woman and would have died more than two centuries ago. Everything about her would have disappeared without a trace upstream in time's long river. If she had been fortunate, her tenth-generation descendants would now be waiting for the selection of the second Swordholder.

But she was alive. She faced the crowd on the plaza. A hologram of her image floated above them like a colorful cloud. A young mother came up to Cheng Xin and handed her baby, only a few months old, to her. The baby giggled at her, and she held him close, touching her face to his smooth baby cheeks. Her heart melted, and she felt as if she were holding a whole world, a new world as lovely and fragile as the baby in her arms.

There were three reasons.

The crowd cried out in joy. The baby in Cheng Xin's arms, startled, began to cry. She held the baby tighter. Do I have another choice?

The answer came to her, brooking no doubt. No. None at all.

First, being declared a savior was just like being pushed under the guillotine: There was no choice involved. This had happened to Luo Ji, and now it was happening to her.

The third fact stood in front of her like an unscalable wall. Even if the first two reasons did not exist, this wall would remain: Yun Tianming.

Second, the young mother and the soft, warm bundle in Cheng Xin's arms made her realize something. She understood for the first time her own feelings toward this new world: maternal instinct. She had never experienced such a feeling during the Common Era. Subconsciously, she saw everyone in the new world as her child, and she could not bear to see them come to harm. Before, she had mistakenly thought of it as a sense of responsibility. But, no, maternal instinct was not subject to rationalization; she could not escape it.

This wasn't a lie. Cheng Xin really had been found. Her mother had never married, but one night, while on a date with her boyfriend at the time, she saw a three-month-old baby abandoned on a park bench, along with a bottle of milk, a thousand yuan, and a slip of paper with the baby girl's birthday. Her mother and the boyfriend had intended to bring the baby to the police, who would have turned the baby over to the city's civil affairs department, who would have sent her to an orphanage.

This situation was a hell, a bottomless abyss, the same as the abyss Yun Tianming had plunged into for her sake. She could not back off now. She had to accept karma. It was her turn.

Cheng Xin's childhood had been full of her mother's love, but only her mother's love. She had asked her mother where her father was. Unlike some other single mothers, her mother responded calmly. She said she didn't know, and then, after a sigh, added that she wished she did. Cheng Xin had also asked her where she had come from, and her mother had told her she was found.

Instead, her mother decided that she wanted to bring the baby home and go to the police in the morning. Perhaps it was the experience of being a mother for a night, or some other reason, but the next morning, she found that she couldn't send the child away. Every time she thought of parting from the young life, her heart ached, and so she decided to become the child's mother.

The boyfriend left her because of this. During the following decade, she dated four or five other men, but all of them ended up leaving her because of Cheng Xin. Later, Cheng Xin found out that none of the men had explicitly objected to her mother's decision to keep her, but if any of them ever showed a trace of impatience or lack of understanding, her mother broke up with him. She refused to let any harm come to Cheng Xin.

When she was little, Cheng Xin never thought her family was incomplete. Instead, she thought it just the way it should be: a small world made up of mother and daughter. The small world possessed so much love and joy that she even suspected that adding a father would be extraneous. Later, she did miss having a father's love -- at first, only a vague sensation, but later a growing ache. And that was when her mother did find a father for her, a very kind man full of love and a sense of responsibility. He fell in love with Cheng Xin's mother in large part because of how much she loved Cheng Xin. And so a second sun appeared in Cheng Xin's life. She felt that her small world really was complete, and so her parents did not have another child.

Later, Cheng Xin left her parents to go to college. After that, her life was like a runaway horse that carried her farther and farther until, finally, not only did she have to part from them in space, but also time -- she had to be sent to the future.

Her mother had held her hand and said, "My darling, the three of us are together because of love…"

That night when she left her parents for the last time would be carved in her mind forever. She had lied to her parents and said that she'd be back the next day -- she couldn't bear to say good-bye, and so she had to leave without saying anything. But they seemed to know the truth.

Cheng Xin spent that night standing in front of her parents' window. In her mind, the night breeze and the twinkling stars and everything else repeated her mother's last words.

Three centuries later, she was finally ready to do something for love. "I will be a candidate for the Swordholder," she said to the young mother.