“When’ve you ever seen a ninja with a gun?” Pancho asked his brother. “We’re going to use traditional weapons: ropes, chains, a lot of shuriken.”

Shuriken were ninja stars. I told Pancho I knew how to make them. My father had taught me to do something similar with a plastic bottle cap and five nails. We used to spend entire afternoons together, throwing them at tree trunks.

We were walking to the plaza to start our “training” when my mom arrived with my sisters. Each of them was carrying an enormous bag. “You guys moving?” joked Pancho. My mother greeted him affectionately and teased him, asking what he was plotting this time. Again, I noticed she looked very young. Her black hair was loose. She greeted each of us with a kiss on the cheek, gave me a long hug, and said they were going to my grandma Clara’s. My little sister hung from my neck and told me she would miss me a lot, but Carola grabbed her from behind and pulled her away. “I want to say goodbye too” was her excuse, but she barely brushed my cheek with a quick kiss. She gave Camilo a few little pats on the cheek—he’d always had a crush on her—and she told my mom and sister to hurry up, they were running late.

We used Plaza San Francisco in Santa Julia for training. It was ideal because it had a playground built of metal and wood where we could exercise without anyone bothering us, since the equipment was so old and shabby that almost no kids ever used it. In the end we couldn’t find much more information about ninjutsu; so just like that, with a little knowledge and no sensei, we trained in the things our intuition told us were essential. Supposedly, ninjutsu meant “the art of stealth,” so we focused especially on learning how to slip away, how to make all our movements silent.

We practiced our balance on the teeter-totter and climbed whatever was in front of us, from the playground equipment to the walls guarding houses or abandoned factories. Sometimes we used ropes, but most of the time we climbed using just our hands. To improve our speed we ran downhill, jumping any obstacle we came upon. The climbing, running, and jumping, though—those were the easy parts. We ended up covered in scrapes and bruises, but we were overflowing with energy, especially Pancho, who jumped higher than anyone in spite of his short legs.

What was really hard for us was learning to move without making noise. Ninjas were so silent that some castles had floors that were specially designed to squeak at the slightest contact. They were called “nightingale floors,” because the alarm they sounded was similar to that bird’s cry. We split up the day to work on the two skills: in the morning we ran all over, and in the afternoon, once our bodies were more tired and less anxious, we set ourselves to quieting our footsteps.