Kappamaki (かっぱ巻き, cucumber thin roll)

A cucumber roll looks like practice food until you make one carefully. Then it becomes a small lesson in the whole sushi counter: fresh ingredient, seasoned rice, clean hands, sharp knife. Nothing hidden. The cucumber must be crisp and cool, because there is no sauce here to forgive a tired one.

The detail that decides kappamaki is restraint. Spread less rice than your hand wants to use, leave the far edge of the nori bare, and place one straight strip of cucumber through the center. Too much rice makes a fat roll that will not close; too much cucumber splits it. A thin roll, hosomaki, is meant to be narrow enough to eat in one bite, not wrestled politely with chopsticks.

Use Japanese cucumber if you can, especially in summer when it is at its shun, its prime. Persian cucumber is a sensible stand-in. If your cucumber is watery, scrape away the seed core and salt the strips briefly, not to season them heavily, but to keep excess water from softening the rice and nori. The real thing is not severe. It is simply exact about where the moisture belongs.

Kappamaki sits easily in a weeknight meal with miso soup and a small pickle, or beside other sushi rolls when the table is fuller. It is often the roll children begin with, and I like that. The first lesson should be clean, green, and possible.