POLINA HAD GONE TO GREAT EFFORTS TO HIDE HER BOOK. IN A CORNER OF THE MUSTY BASEMENT OF HER HOUSE, SHE PUSHED ASIDE A HEAVY-LOOKING BARREL. KNEELING DOWN, she lifted a piece of the floor under it. The thud it made when she set it down made me think she must be very strong. She reached into the space and pulled out a small book, its cover gone.

“Always arrange things so that if you hear someone coming you can make things look normal quickly,” she cautioned me as she pushed the barrel nearer to the hole and moved the piece of floor to partially cover it.

I nodded, feeling alert, anxious to know what Polina knew.

She thumbed through the book, which measured about three by five inches. “Is that The Deadly Partisan?” I asked.

She looked up at me. “Don’t say its name so easily.”

“Why is it so much worse to be a partisan than a soldier?”

“Because we’re an unknown,” she answered, continuing to skim through the book. “We’re unpredictable. They don’t know who we are or what we’ll do.”

“Do the Germans know children act as partisans?”

“Probably. Our job is to make sure they don’t know that these children are partisans.”

I gazed over Polina’s shoulder as she skimmed the index. “This whole first part is about guns and hand grenades and bayonets. We’ve only got a little time…. Let’s pick three things.”

What a smart girl, I thought, a natural leader.

“I’m going to teach you how to disarm someone who’s attacking you with a knife. Then … how to use wire against a motorcyclist, and … oh, how to tie the five basic knots. Very important.”

She put the book down. “I’ll be the knife attacker first, then you. If you feel what it’s like as the attacker and the one being attacked, you’ll understand it completely.”

She grabbed a rough piece of wood about nine inches long from a stack of odds and ends in the corner. Bending her knees slightly, she glided first to the left and then to the right, as if she were stalking her prey, almost circling me, using the wood as a stand-in for a knife. I moved along with her, keeping my distance, trying to figure out how she would attack me first — aiming for my stomach? My throat? My arm? Suddenly, she leapt at me, her right hand holding the “knife” high. It looked like she meant to bring it down with all the force of her body into my upper chest.

I turned to my left to run away and felt a stab on my right shoulder almost immediately.

“Bad move,” Polina said matter-of-factly as she walked away from me, her body looking completely relaxed and in control. “First of all, you offered no defense. You didn’t even try to disarm me. Second, if you’re going to run, turn in the direction of your dominant hand — right, in your case — so that if you get knifed in the shoulder like you did just now, at least you’ll be able to use your good hand and arm. Because your attacker will try to knife you more than once, just to be sure.”

“Sure of what?” I rubbed my shoulder. Polina had hit me pretty hard with that piece of wood.

“That you’re dead. And you would be if you’d really met an enemy like me.”

Her skill and the feeling of vulnerability I felt being such an easy target made me determined to learn quickly.

“Listen carefully,” Polina said. “Here’s what you do when someone has a knife and they’re attacking you overhanded, like I just did. Okay: The knife is coming down at you. You put both your hands up to catch the arm at the wrist. Keep your right hand higher than the left, but just a little. Here, you take the knife. We’ll do it in slow motion. Come at me, that’s it. Now, as you’re bringing it down, my hands go up so they’re in a sort of V or U shape. You’re going to use your thumbs — because they’re so strong — and you’re going to hook the right one into the crook of your attacker’s pinkie, and your left thumb into the same place but on his ring finger.”

Her hands were up to catch my downward thrust. They were amazingly strong. “Do you feel where my fingers are?”

“Yes.”

“I’m going to press hard while I pull your arm to the left.”

“Not too hard,” I said, still feeling a dull pain in my back from her first demonstration.

“Don’t be a baby,” she said as she pressed her thumbs hard into the tender joints that connected my pinkie and ring finger to my hand, pulled me with incredible strength to the left, and threw me to the ground before I could so much as yell.

I lay on the floor staring up at her, stunned. “How did you do that?”

She smiled proudly. “Just like I told you. Hands catch the arm in a V, thumbs in the two sockets, press hard, pull left, and throw to the ground.” She was sort of bouncing on the balls of her feet like a skinny little boxer, proud to have her opponent on the ground.

“Let’s try it again,” I said. On our first attempt I forgot to push my hands up hard, and she got me in the shoulder again. But I remembered to turn right, so she got the other shoulder, and just barely.

“You move fast, that’s good,” she observed. “One more time. Forget I’m a friend. Forget I’m a girl.” It wasn’t easy to think that way, but I closed my mind to emotion and had her on the ground in seconds. I stood tall, smiling down at her. She slowly rolled on her side, pushed herself up on her elbow, and gasped for air.

“Oh, Polina!” I knelt down next to her. “I’m sorry. I didn’t mean to hurt you!”

It took her a few more seconds to catch her breath. “It’s all right,” she said finally. “You knocked the wind out of me. You learn fast.” We smiled and even laughed a little, and our eyes met; I think at that moment I had her full acceptance into their little group.

“There’s another way to do it,” she said, struggling a little as she got to her feet.

“Is it harder or easier?”

“Both.”

“Do you want to rest a minute?”

“Don’t be ridiculous.” This time she had me catch her knife-holding wrist with one arm, grab her other elbow, and pull her toward me. If the attacker was short enough, I was to thrust my head up under his chin and knock his head back. If he was tall, I was to aim for his solar plexus, right where the ribs separate.

“This one’s easier,” I said, after trying it a few times both as attacker and victim.

“Yes, but it’s a little more dangerous, because instead of throwing your attacker away from you and to the ground, you’re pulling him toward you. You’re using your own body as a weapon.”

I nodded, thinking how much different it would be in real life to fight off an attacker. There was the element of surprise, the fear I might be feeling, the strength of my opponent, his training, how fast it happened, and my memory of how to disarm him that would all come into play.

“You mentioned knots earlier,” I said. “Why do I need to know about knots?”

“Because you can do anything with knots. You can tie a wire between two trees across a road where you know an enemy motorcyclist will pass. You tie it at the height of his neck. He can’t see it, but it will knock him off his motorcycle. If you don’t know your knots, you’ll miss your chance.”

I couldn’t help but smile. “So warfare is really about knowing how to tie knots?”

“Precisely! First, put the book back. Move the barrel back on top of it, and then I’ll teach you the hitch knot. It’s so useful. If you want to —”

Suddenly, the basement door creaked open. Our heads snapped toward the top of the stairs. “Polina, is that you?” It had to be her mother. The voice sounded clouded and scratchy, like it wasn’t used much.

“I’ll be right there!” Then, in a whisper, she said, “Ivan, put everything back, and then go to Miss Galina’s. We’ll practice more later. Wait one minute after I’ve gone, then leave by the back door. Don’t say good-bye, and don’t let my mother see you.”

I nodded, and she ran up the stairs. I counted to sixty and slipped out of her house unnoticed. My life as a partisan had begun.