The enemy began to contract slowly, not wanting to come within range until all their weapons could be brought to bear at once. Then Ender began to work in earnest. His reserve screen approached the outside of the globe, and the enemy began to concentrate his forces there. Then Bean's force appeared on the opposite side, and the enemy again deployed ships on that side.

Which left most of the globe only thinly defended. Ender's bullet attacked, and since at the point of attack it outnumbered the enemy overwhelmingly, he tore a hole in the formation. The enemy reacted to try to plug the gap, but in the confusion the reserve force and Bean's small force attacked simultaneously, while the bullet moved to another part of the globe. In a few more minutes the formation was shattered, most of the enemy ships destroyed, and the few survivors rushing away as fast as they could go.

Ender switched the simulator off. All the lights faded. Mazer was standing beside Ender, his hands in his pockets, his body tense. Ender looked up at him.

"I thought you said the enemy would be smart," Ender said.

Mazers face remained expressionless. "What did you learn?"

"I learned that a sphere only works if your enemy's a fool. He had his forces so spread out that I outnumbered him whenever I engaged him."

"And?"

"And," Ender said, "you can't stay committed to one pattern. It makes you too easy to predict."

"Is that all?" Mazer asked quietly.

Ender took off his radio. "The enemy could have defeated me by breaking the sphere earlier."

Mazer nodded. "You had an unfair advantage."

Ender looked up at him coldly. "I was outnumbered two to one."

Mazer shook his head. "You have the ansible. The enemy doesn't. We include that in the mock battles. Their messages travel at the speed of light."

Ender glanced toward the simulator. "Is there enough space to make a difference?"

"Don't you know?" Mazer asked. "None of the ships was ever closer than thirty thousand kilometers to any other."

Ender tried to figure the size of the enemy's sphere. Astronomy was beyond him. But now his curiosity was stirred.

"What kind of weapons are on those ships? To be able to strike so fast?"

Mazer shook his head. "The science is too much for you. You'd have to study many more years than you've lived to understand even the basics. All you need to know is that the weapons work."

"Why do we have to come so close to be in range?"

"The ships are all protected by forcefields. A certain distance away the weapons are weaker and can't get through. Closer in the weapons are stronger than the shields. But the computers take care of all that. They're constantly firing in any direction that won't hurt one of our ships. The computers pick targets, aim; they do all the detail work. You just tell them when and get them in a position to win.

All right?"

"No," Ender twisted the tube of the radio around his fingers. "I have to know how the weapons work."

"I told you, it would take—"

"I can't command a fleet—not even on the simulator—unless I know." Ender waited a moment, then added, "Just the rough idea."

Mazer stood up and walked a few steps away. "All right, Ender. It won't make any sense, but I'll try.

As simply as I can." He shoved his hands into his pockets. "It's this way, Ender. Everything is made up of atoms, little particles so small you can't see them with your eyes. These atoms, there are only a few different types, and they're all made up of even smaller particles that are pretty much the same.

These atoms can be broken, so that they stop being atoms. So that this metal doesn't hold together anymore. Or the plastic floor. Or your body. Or even the air. They just seem to disappear, if you break the atoms. All that's left is the pieces. And they fly around and break more atoms. The weapons on the ships set up an area where it's impossible for atoms of anything to stay together.

They all break down. So things in that area—they disappear."

Ender nodded. "You're right, I don't understand it. Can it be blocked?"

"No. But it gets wider and weaker the farther it goes from the ship, so that after a while a forcefield will block it. OK? And to make it strong at all, it has to be focused so that a ship can only fire effectively in maybe three or four directions at once."

Ender nodded again, but he didn't really understand, not well enough. "If the pieces of the broken atoms go breaking more atoms, why doesn't it just make everything disappear?"

"Space. Those thousands of kilometers between the ships, they're empty. Almost no atoms. The pieces don't hit anything, and when they finally do hit something, they're so spread out they can't do any harm." Mazer cocked his head quizzically. "Anything else you need to know?"

"Do the weapons on the ships—do they work against anything besides ships?"

Mazer moved in close to Ender and said firmly, "We only use them against ships. Never anything else. If we used them against anything else, the enemy would use them against us. Got it?"

Mazer walked away, and was nearly out the door when Ender called to him.

"I don't know your name yet," Ender said blandly.

"Mazer Rackham."

"Mazer Rackham," Ender said, "I defeated you."

Mazer laughed.

"Ender, you weren't fighting me today," he said. "You were fighting the stupidest computer in the Command School, set on a ten-year-old program. You don't think I'd use a sphere, do you?" He shook his head. "Ender, my dear little fellow, when you fight me, you'll know it. Because you'll lose." And Mazer left the room.

Ender still practiced ten hours a day with his toon leaders. He never saw them, though, only heard their voices on the radio. Battles came every two or three days. The enemy had something new every time, something harder—but Ender coped with it. And won every time. And after every battle Mazer would point out mistakes and show Ender that he had really lost. Mazer only let Ender finish so that he would learn to handle the end of the game.

Until finally Mazer came in and solemnly shook Ender's hand and said, "That, boy, was a good battle."

Because the praise was so long in coming, it pleased Ender more than praise had ever pleased him before. And because it was so condescending, he resented it.

"So from now on," Mazer said, "we can give you hard ones."

From then on Ender's life was a slow nervous breakdown.

He began fighting two battles a day, with problems that steadily grew more difficult. He had been trained in nothing but the game all his life, but now the game began to consume him. He woke in the morning with new strategies for the simulator and went fitfully to sleep at night with the mistakes of the day preying on him. Sometimes he would wake up in the middle of the night crying for a reason he didn't remember. Sometimes he woke up with his knuckles bloody from biting them. But every day he went impassively to the simulator and drilled his toon leaders until the battles, and drilled his toon leaders after the battles, and endured and studied the harsh criticism that Rackham piled on him.

He noted that Rackham perversely criticized him more after his hardest battles. He noted that every time he thought of a new strategy the enemy was using it within a few days. And he noted that while his fleet always stayed the same size, the enemy increased in numbers every day.

He asked his teacher.

"We are showing you what it will be like when you really command. The ratios of enemy to us."

"Why does the enemy always outnumber us?"

Mazer bowed his gray head for a moment, as if deciding whether to answer. Finally he looked up and reached out his hand and touched Ender on the shoulder. "I will tell you, even though the information is secret. You see, the enemy attacked us first. He had good reason to attack us, but that is a matter for politicians, and whether the fault was ours or his, we could not let him win. So when the enemy came to our worlds, we fought back, hard, and spent the finest of our young men in the fleets. But we won, and the enemy retreated."