Drizzle a little soy sauce over the bonito flakes. Pit and break up the umeboshi. Sprinkle a little salt over the nori sheet.

Spread a thin layer of rice over the nori, then scatter the seasoned bonito flakes on top.

Fold the corners of the nori over and press gently with your hands, then flip it over. (The steam will help the corners stick.)

Do the same with the umeboshi filling.

Let both rice balls rest after flipping them over.
Then cut in half and serve on a plate.

How about the half-size version? Use hand roll nori sheets and just fold them in half, following the same steps.

For the half-size, sprinkle salt on the nori, add rice, sliced cheese, soy sauce, and, if you like, shiso leaves. Fold in half. Mayonnaise also goes well!

If you add too much rice or filling to the half-size, it might spill out, so wrapping it in plastic wrap can help. It's easy to eat on the go and keeps your hands clean!

Tip: To keep the filling from spilling out without using plastic wrap, don't spread the rice all the way to the edges. Use just enough rice so you can see the nori through it, and place the filling on one side only.

If you press the edges of the nori together, the rice won't fall out. You can also shape it like a triangle if you want!

Update: I used to wipe my knife with a damp paper towel when cutting, but thanks to advice from Koumasa-mam and Cook Ako,

If you cut the onigirazu while it's still wrapped in plastic, the cross-section looks really nice. Plus, you can carry it as is! Thanks for the tip!

This recipe was also featured in a Cookpad book! I'm so happy—it's a treasure!

Thank you, everyone!

I was so surprised that the sushi rice version was also featured!