Onigiri (Rice Balls)

Name: Onigiri (Rice Balls)
Prep time: 15 min
Total time: 15 min
Yield: 2 servings
Cuisine: Japanese
Ingredients: 2 bowls Warm cooked rice; 0.5 tsp Salt; 2 sheets Nori (roasted seaweed); 2 Umeboshi (pickled plum); 3 tbsp Tuna mayo; 60 g Grilled salmon; 1 to taste Katsuobushi + soy

Japanese rice balls: warm rice shaped around a filling like umeboshi, tuna mayo, or salmon, then wrapped in nori. With just salted water on your hands, anyone can make them — perfect for lunchboxes and snacks.

Ingredients

2servings

Warm cooked rice · about 300g, short-grain2 bowls
Salt · rubbed on hands0.5 tsp
Nori (roasted seaweed) · quartered2 sheets
Filling (pick one)
Umeboshi (pickled plum) · pitted2
Tuna mayo · tuna + mayonnaise3 tbsp
Grilled salmon · flaked60 g
Katsuobushi + soy · okaka1 to taste

Steps

Use freshly cooked rice, slightly cooled but still warm (too hot burns your hands; too cold won't hold together).
⏲ 1 min
Prep the filling: mix tuna with mayo, pit the umeboshi, or grill and flake the salmon.
⏲ 5 min
Wet your hands lightly and rub on a little salt (keeps rice from sticking and seasons it).
⏲ 30 sec
Spread a handful of rice on your palm, make a dent, add a teaspoon of filling, and cover it with rice.
⏲ 1 min
Gently shape into a triangle with both hands (don't squeeze hard — just turn and press lightly 3–4 times).
⏲ 1 min
Wrap with a strip of nori and plate. Eat right away or pack into a lunchbox.
⏲ 30 sec

Variations

Yaki onigiri: Brush with soy and grill or pan-fry for a crisp crust.
Tuna mayo / mentaiko / salmon / umeboshi: Swap the filling freely.
Korean jumeokbap: Mix rice with sesame oil, salt, nori flakes, and tiny anchovies, then roll into balls.
Onigirazu: Wrap rice and filling flat in nori for a 'rice sandwich.'

Tips

Shape the rice while fresh and warm so it holds (cold rice crumbles).
Wet hands with salted water so it won't stick and gets seasoned.
Don't squeeze hard — shape gently so it stays fluffy once cooled.
Add the nori just before eating for crispness; pack it separately for lunch.
Keep the filling small and centered.

More detail and the reasons why (5)

"While warm" is a statement about starch, not temperature. Cooling rice recrystallises its starch — retrogradation. Dishes use that one phenomenon in different directions (cooking rice), and onigiri belongs to the group that shapes it before retrogradation begins. Cold rice crumbles not for want of force but because each grain has already set and stopped gripping its neighbours, which is why pressing harder does not rescue it.
Spam musubi pushes the same property further and arancini runs it backwards. Musubi is pressed into its mould while the rice is hot, because only before retrogradation will it compact into one block. Arancini uses rice fully cold, since the starchy paste between the grains, setting firm as it retrogrades, is the only thing binding it. Onigiri sits between the two.
"Do not squeeze" and "it has to hold together" are not in conflict. The holding is done by surface starch; what your hands add is crushing. Burst grains turn pasty and set hard as they cool. Three light turns to find the shape and then stop gives something that survives hours in a bag and still falls apart in the mouth.
The salted water is seasoning and a surface treatment at once. Salt does not travel into the centre; it stays on the outside — and the outside is the layer that dries and spoils first. In a packed lunch the salt is both seasoning (salt and seasoning) and a very mild preservative. Gimbap does the same job with sesame oil and salt and, using no vinegar, keeps less well than sushi for exactly that reason.
Why the nori goes on at the last moment. Nori is thin and dry and pulls moisture out of the rice fast. Wrapped early it loses its crispness and dries the rice surface as well. The two-layer convenience-store wrapper exists to solve this one problem.