Stuffed with a variety of fillings and flavors, these rice balls make an ideal quick snack and are a fun alternative to sandwiches for lunch. In this recipe, you’ll learn how to make onigiri (musubi) using the common ingredients for rice balls in Japan.
Onigiri, also known as Japanese rice ball is a great example of how inventive Japanese cuisine can be. It is also a Japanese comfort food made from steamed rice formed into the typical triangular, ball, or cylinder shapes and usually wrapped with nori (dried seaweed).
What is Onigiri (Omusubi)
Onigiri (おにぎり) or sometimes called Nigirimeshi (握り飯) or Omusubi (おむすび; in English, however, it’s also called Musubi but not used in Japan) is a Japanese rice ball made of rice formed into triangular or cylindrical shapes and often wrapped in nori. It’s often stuffed with various fillings.
Onigiri vs. Sushi
If you are new to Japanese cuisine, sometimes onigiri is misunderstood as a type of sushi but it is not.
One of the key differences between onigiri and sushi is that onigiri is made with plain steamed rice, while sushi is made of steamed rice seasoned with vinegar, salt, and sugar.
Because of its popularity in Japan, all different appetizing flavors/fillings of onigiri can be found in Japanese convenience stores. You can even buy onigiri from specialty stores for take-out.
At the time onigiri were first invented, refrigerators didn’t exist yet. So the Japanese came up with a method to keep the rice fresh longer by filling it with salty or sour ingredient as natural preservatives. That’s why salt is rubbed on hands when you make onigiri so that rice is kept safe for a longer time.
The most common fillings for onigiri in Japan include:
- sha-ke (salted salmon)
- umeboshi (Japanese pickled plum)
- okaka (bonito flakes moistened with soy sauce)
- kombu (simmered kombu seaweed)
- tuna mayo (canned tuna with Japanese mayonnaise)
- tarako (salted cod roe) – not in the picture
Nowadays onigiri fillings and flavors are more creative! It is an inventive way to use up any leftovers from the previous dinner like Chicken Karaage and Shrimp Tempura. Some onigiri also uses mixed rice Takikomi Gohan instead of plain white rice.
Formed into a compact form, these little rice balls make rice portable and easy to eat with hands. You can enjoy onigiri for a quick snack, or as school/ work lunch or picnic food. They are also commonly included in bento boxes.
Tips & Techniques of Making Onigiri
1. Use Freshly Cooked Rice
Let the cooked rice cool just slightly before making them. It should be warm/hot when you make onigiri.
2. Wet Your Hands
It’s important to wet your hands with water to prevent the rice from sticking. Prepare a bowl of water next to your working station.
3. Salt Your Hands
Salt both your hands and rub to spread all around. This helps to keep the onigiri for a longer time as well as flavoring the onigiri.
4. Give Just Enough Pressure
Your hands should be just firm enough when pressing the onigiri so the rice doesn’t fall apart and shape into the typical triangle, ball, or cylinder shapes. You don’t want to squeeze the rice too tight.
5. Use Kitchen Towel to Save for Next Day
If you want to make onigiri for lunch the next day but don’t want to wake up early, here’s my tip. You can wrap the finished onigiri (in plastic wrap) with a thick kitchen towel to protect from being too cold in the refrigerator. Rice gets hard in the refrigerator but with this easy trick, your onigiri will be cool enough to stay safe.
Like everything else, practice makes perfect when comes to making onigiri. For a visual guide, you can watch my video and see step-by-step instructions below.
The best part about making onigiri at home is you can always engage your little ones as their ‘craft day in the kitchen.’ Make it fun and enjoyable!
Tenmusu (Rice Ball with Shrimp Tempura)
Onigiri (Japanese Rice Balls)
For Steamed Rice
- 2 cups uncooked Japanese short-grain rice
- 2 ½ cups water
For Making Onigiri
For Salted Salmon
- 1 fillet salmon
- kosher or sea salt (I use Diamond Crystal; use half for table salt)
- Gather all the ingredients.
To Prepare Steamed Rice
- Put the rice in a large bowl and gently wash the rice in a circular motion and discard the water. Repeat this process about 3-4 times.
- Let the rice soak in water for 30 minutes. Transfer the rice into a sieve and drain completely, at least 15 minutes.
- Combine the rice and water in a heavy-bottom pot. A heavy-bottom pot with a tight-fitting lid is recommended as it is thicker at the base so it absorbs and distributes heat better. Cover the lid and bring it to a boil over medium heat.
- Once water is boiling, turn the heat to the lowest setting and continue to cook covered for 12 to 13 minutes, or until the water is completely absorbed. At 12-13 minute mark, take a quick peek and if you see there is any water left, close the lid and continue cooking for another minute or so.
- Remove the pot (with the lid on) from the heat and let it steam for another 10 minutes. Then transfer the rice to a large plate or baking sheet lined with parchment paper (I use Sushi Oke). Fluff the rice with a rice scooper. Let the cooked rice cool a little bit until you can hold rice without burning your hands. However, do not let the rice completely cool down.
To Prepare Onigiri Fillings
- While rice is being soaked and drained (45 minutes), prepare the onigiri fillings.
- Salted salmon filling: Sprinkle kosher salt on both sides of the salmon fillet. Bake at 425ºF (218ºC) in a toaster oven or oven for 10-20 minutes. Japanese salted salmon is cooked till well done (more dry and flaky).
- Break the cooked salmon into flakes and set aside.
- Umeboshi filling: Place umeboshi (Japanese pickled plums) on a 10” x 10” sheet of plastic wrap. Fold in half and squeeze the seed out from each umeboshi. Discard the seeds and keep the umeboshi flesh.
- Okaka filling: Put katsuobushi (dried bonito flakes) in a bowl and add 2 Tbsp soy sauce. Mix to combine. Katsuobushi should be moistened but not drenched in soy sauce.
- Tuna mayo filling: Put drained canned tuna in a bowl and add 2 Tbsp Japanese mayonnaise and ½ Tbsp soy sauce. Mix to combine.
- Seasoned kombu filling: Put the purchased seasoned kombu in a bowl for easy access later.
To Make Onigiri
- Cut the nori sheets in thirds (⅓).
- First, wet both of your hands with water in order to prevent the rice from sticking to your hands.
- Then put some salt in your hands and rub to spread all around your palms. How much salt? I dip 3 finger tips in kosher salt shown in the picture below. If you are using table salt, use half amount as it’s saltier than kosher salt.
- Scoop out a handful of warm rice (about ⅓ cup) into one hand. Create a small well (indentation) in the center of the rice. Put one kind of filling (about 1-2 tsp) inside. Then mold the rice with your hands around the well to cover your filling completely.
- Press the rice around the filling to gently form the rice into a triangle. I use three fingers (thumb, index finger, middle finger) to make a triangle corner. Your hands should be just firm enough so the onigiri doesn’t fall apart. You don’t want to squeeze the rice too tight.
- Wrap the onigiri with nori seaweed.
- Place a little bit of each filling on top of onigiri so we know which kind it is.
Alternative Method of Making Onigiri
- If you do not want to touch the rice at all, you can place a piece of plastic wrap in a rice bowl (or any small bowl) and put the rice on top. Sprinkle some kosher salt (remember, salt is used to preserve the rice for a long time here).
- Pull the plastic wrap corners and twist a few times.
- Form into a triangle shape with the same manner as I described above.
- Onigiri (or any rice dish) gets hard when you refrigerate. The cold air makes the rice dry and hard (which is perfect for fried rice!). I don't recommend making onigiri ahead of time. But if you really need to, my trick is to wrap the onigiri with thick kitchen towels and store in the fridge. Onigiri will be cool and safe, but should not be cold.
Editor’s Note: The post was originally published on September 5, 2012. The video is added in September 2017 and images were updated.