Onigiri Rice Balls Recipe (Bonito Soy Sauce & Tuna Mayonnaise)

This is a dish made by forming rice into triangles or ball shapes and then eaten by hand. It’s a dish with a certain texture and delicious flavor different from rice eaten from a bowl. Learn the technique for making rice balls.

• by Yuko Ihara

Onigiri is a way of eating rice that has been passed down from long ago in Japan. Its name comes from the action of holding and squeezing the rice in one’s hands (“握る” / “nigiru” in Japanese). Since Onirigi is easy to carry around and can be eaten using just one hand, it’s common as a portable food for fieldwork and travel, and also works well packed in “bento” lunchboxes. You can enjoy lots of Onigiri variations by filling the inside with ingredients or adding flavoring on the outside of the rice ball!

Rice alone is not salty and does not have a robust flavor. Therefore, it is necessary to sprinkle salt on Onigiri or season the rice and fillings with ingredients like soy sauce. Soy sauce, in particular, has a flavor and umami that goes well with rice, making it a good match for Onigiri. It enhances the deliciousness of the rice.

When squeezing the rice in your hands, squeezing with too much force will cause the rice to tightly harden. Instead, squeezing gently only so that the rice does not fall apart will better allow you to enjoy the delicious flavor of the rice. If possible, roll the rice ball in your hand to shape its surface and form the overall ball. After making several rice balls, you’ll get used to this process!

warm rice - 400g (14.1 oz.)

salt - as needed

yaki-nori (dried seaweed) - as needed

vegetable tsukemono (if available / desired assortment) - as needed

dried bonito shavings - 4g (0.14 oz.)

Kikkoman Soy Sauce - 2 tsp

tuna (canned, drained) - 20g (0.7 oz.)
mayonnaise - 10g (0.35 oz.)
Kikkoman Soy Sauce - 1 tsp
white roasted sesame seeds - ½ tsp

One type of maze-gohan Onigiri can be made by mixing boiled chickpeas and cumin seeds with Kikkoman Soy Sauce. Another type uses minced Italian parsley mixed with salt and lemon zest for a refreshing aroma. For these, squeeze the rice balls into a flatter disc-like shape.

We also recommend trying Onigiri wrapped in dry-cured ham (prosciutto) instead of seaweed. Make your Onigiri even tastier by using salty fillings, or using salt or soy sauce to season the rice! One variation of this uses sun-dried tomatoes in oil mixed with Kikkoman Soy Sauce. Another way to make this is by using oil-soaked sardines mixed with Kikkoman Soy Sauce, and rolling the rice into triangular balls. After wrapping each type with the ham, you can put a little of the filling ingredients atop each Onigiri so it’s easier to tell which filling is inside.

Since Onigiri is put together using only rice, it is best to avoid using rice that is dry or not sticky. Use japonica rice, which turns sticky and shiny when cooked. Overseas, brands of rice produced in North America and Europe, such as Nishiki and Tamanishiki, are widely loved as rice suitable for Japanese cuisine.

Popular fillings that have been commonly eaten for centuries and are still popular today are kelp pickled in salt or made into “tsukudani”; salted salmon that has been baked and squashed; and pickled Japanese apricots (“umeboshi”). You can use any ingredient as a filling as long as it’s not too watery and its flavor goes well with rice.

Although triangular rice balls are the standard, round ball shapes or flatter disc-like shapes, as well as rectangular shapes also exist. Use whatever shape you like for your Onigiri!

Yes. You can hold the rice in a sheet of parchment paper and wrap it this way to make the same shape.

If you are not used to squeezing Onigiri rice balls using your hands, you can use a kitchen tool called an “Onigiri-gata” (Onigiri mould) that allows you to make nice, uniform shapes! These moulds come in a variety of different shapes and materials.

Press the rice into the mould, then remove it to achieve a beautiful shape. When making filled Onigiri, put only half of the rice into the mould first, the press the filling into the center, and then put more rice on top and then form the rice ball’s shape in the mould.

Onigiri rice balls have come to be valued as portable food because they are easy to carry. In the past, Onigiri would be kept in bamboo baskets like the one shown in the photo. Lightweight, sturdy, and breathable, bamboo also has antibacterial properties, making it a perfect choice for a bento box!

Having lived in England and the U.S., Yuko Ihara is well-versed in a wide range of culinary genres. As a culinary researcher, she creates dishes for magazines and books, develops corporate menus, and also engages in product development and food consulting. She introduces easy-to-follow tips on how to make delicious food at home, emphasizing the importance of seasonality and healthful eating. When travelling, she loves to search for delicious vegetables and ingredients.

Instagram: @iharayukoo