Tenmusu is crispy shrimp tempura tucked in a rice ball and wrapped with nori seaweed. This delicious Nagoya specialty is now found throughout Japan in convenience stores and bento shops. Make it fresh at home for a fun lunch or snack!
When you visit Nagoya, the largest city in the Chūbu (central) region of Japan, there are many unique “Nagoya Foods” (Nagoya-meshi 名古屋めし) that you’ll need to experience. I’ll be sharing a series of food recipes that originated from Nagoya on Just One Cookbook and the first one is Tenmusu (天むす).
What is Tenmusu?
Tenmusu (天むす) are rice balls with shrimp tempura as a filling, wrapped with nori (seaweed). It has a distinctive look as it shows the part of shrimp tempura exposed at the top of the rice ball.
The word “Tenmusu” comes from two words combining – Tempura (天ぷら) and Omusubi (おむすび) – which means rice ball in Japanese. Japanese likes to shorten names by picking the first few syllables of the words; hence, we end up with Ten(pura) + (o)musu(bi).
I assume many of you are already familiar with Onigiri (recipe here) filled with pickled plum (Umeboshi), bonito flakes with soy sauce (Okaka), salted salmon (Sha-ke), and seasoned seaweed (Kombu) such as the ones in the image below.
But you’ve probably haven’t had a chance to try a rice ball with shrimp tempura. As I love the crispy texture of tempura (or any crispy foods for that matter), I was very skeptical about crispy and oily foods being inside onigiri. I’ve never made it at home or purchased it from a store until I went to Nagoya this time. I admit, it completely blew my mind! As the saying goes, always taste something first before making up your mind. You never know, you might love it.
How Tenmusu Became Popular…
If you love the history of food, this one is quite interesting. Although Tenmusu is known as one of the popular “Nagoya Foods” or Nagoya-meshi, we need to give the proper credit to a tempura restaurant called “Senju” (千寿) in Tsu city (located in Mie Prefecture in central Japan) for Tenmusu’s origin.
Back in the 1930s, Mrs. Mizutani, the owner of the tempura set-meal restaurant (天ぷら定食店) was too busy to make lunch for her husband so she quickly made him rice balls with shrimp tempura. At that time she cut the shrimp tempura in half and stuffed the tempura inside so the rice balls didn’t show any part of tempura.
By the 1950s, this dish was being served as an employee meal at the restaurant. As Mrs. Mizutani continued to improve her recipe, Tenmusu became a secret menu for patrons, then later became a formal menu item at Senju.
In 1980, a man called Mr. Fujimori closed his watch shop in Nagoya due to the economic recession. Mrs. Fujimori was thinking of a way to make money to help support the family and remembered the delicious Tenmusu she had at Senju when they went to the beach nearby.
Mrs. Fujimori went to the restaurant and asked Mrs. Mizutani to see if they can teach her Tenmusu recipe, but she quickly got rejected. She didn’t give up and continued to visit the restaurant frequently and even Mrs. Mizutani’s house for a month.
As a result of negotiation, Mrs. Mizutani finally gave in. Mrs. Fujimori got their Tenmusu recipe and permission to start a branch, and that’s how the first branch of Senju was born in Nagoya.
It wasn’t easy for Mrs. Fujimori in the beginning as no one knew what Tenmusu was. However, with the help of TV features and celebrities’ mentions of her Tenmusu, it became quite popular in Nagoya city. This food item then spread throughout Japan as “Nagoya’s specialty” (名古屋名物).
So what happened to Mrs. Mizutani’s tempura restaurant Senju in Tsu city? It became a Tenmusu specialized restaurant and this store has “Original” (Ganso 元祖) in front of the name. The small store has 8 counter bar seats where you can order Tenmusu and miso soup, but most customers come in for takeout (¥1040 for 8 pieces). And just like how Mrs. Mitzuani used to make them, the “original” Tenmusu don’t show the shrimp tempura.
These days you can easily find Tenmusu available throughout Japan, in convenience stores, bento shops or onigiri specialized shops. Other Tenmusu specialized shops such as Jiraiya (地雷也) has branches in Tokyo and Osaka.
If you don’t have plans to visit Japan, don’t worry, with my recipe you can make it at home!
Tips for Making Tenmusu
Even though it’s easy to make Tenmusu, you have to know a few key points before making them.
- Warm Japanese Rice: Please, please, please use Japanese short-grain rice when you make rice balls; otherwise, your rice will not form into a ball. And always make rice balls with warm rice (“warm” but still cool enough that you can handle ).
- Size of Shrimp: Depending on the size of the shrimp you buy, you’ll need to adjust the rice ball size. If you use smaller shrimps than I did in this recipe, you’ll be making smaller rice balls to get the right balance between rice and shrimp tempura. If your shrimps are too big, you can cut them in half.
- Deep-Frying: Sorry, there is no alternative for deep frying if you want to make authentic Tenmusu here. Trust me, it’ll be worth it at the end! 🙂
- Tempura Batter: You can use the batter from my Shrimp Tempura recipe, but I made the egg-free tempura batter this time. Make sure to keep the consistency thicker similar to the ones for fritters. Thick batter absorbs more sauce; thus, tastier!
- Tempura Dipping Sauce: The flavors of Tenmusu comes from Tempura sauce soaked by the shrimp tempura. If you have the tempura sauce handy already, use it. Otherwise, you can use a convenient bottle of Mentsuyu. Mentsuyu is a noodle soup base or multi-purpose sauce for noodles and seasoning). You can buy it online or make it from scratch (easy!).
- Making Rice Balls: Don’t worry about forming your rice balls into a perfect triangle shape. Look, mine isn’t, yet still DELICIOUS. 😉
- Nori (Seaweed): Nori will be wilted (not crispy) after you wrap around the warm rice, and that’s how Tenmusu is served. If you prefer “crispy” nori texture, you can put nori on when you are ready to eat. You can save or pack nori strips in an airtight bag or wrap in a plastic wrap to enjoy later. I don’t have a problem with biting off the wilted nori, but I heard from some of you that that’s not your preference. I’m not sure if this helps, but I usually pick better or best quality nori that is available at my local Japanese grocery store.
- Serve & Store at Room Temperature: Rice balls are always served slightly warm or at room temperature. The cooked rice gets hard when you keep it in the cool/cold place (like a refrigerator). Therefore, we often keep rice balls at room temperature until you are ready to eat. That’s why it’s important to use salt when you make rice balls because salt helps preserve the food safely. However, on a hot and humid day when food gets spoiled fast, keep it in the refrigerator. My trick is to wrap the plate (of rice balls covered with plastic) with a kitchen towel so the rice doesn’t get too cold.
Tenmusu (Tempura Shrimp Rice Ball)
For the Steamed Rice
- 1½ cups uncooked Japanese short-grain white rice (2 rice cooker cups, 360 ml)
- 1⅔ cups water (for cooking the rice)
For the Rice Balls
- Gather all the ingredients. For the steamed rice, please note that 1½ cups (2 rice cooker cups, 300 g) of uncooked Japanese short-grain rice yield 4⅓ cups (660 g) of cooked white rice. See how to cook Japanese rice with a rice cooker, pot over the stove, Instant Pot, or donabe. For this recipe, cook 1½ cups uncooked Japanese short-grain white rice in 1⅔ cups water. While the rice is cooking, prepare the shrimp tempura.
To Make the Shrimp Tempura
- Peel off the shells (easy to start from the 3rd segment) and tails of 12 medium shrimp. Using a skewer, devein the shrimp. The black vein that runs along the back of the shrimp is the intestinal tract.
- Place the shrimp in a bowl and add 1 Tbsp potato starch or cornstarch and a little bit of water. Rub the shrimp with your hands. This is a pretty common trick in Japan, which helps shrimp become more plump and delicious.
- Discard the dirty water and rinse the shrimp a couple of times under cold running water. Drain well and pat dry with a paper towel.
- Heat 2 cups neutral oil to 340–350ºF (170–180ºC). If you make 12 shrimp, 2 cups of oil is a good amount for deep-frying; however, use a smaller pot so that oil is deep enough.
- Sift ½ cup cake flour and 1 Tbsp potato starch or cornstarch with a fine mesh strainer. This will help the tempura batter become light and crispy.
- Add ⅓ cup ice water, 1 Tbsp rice vinegar (unseasoned), and ½ Tbsp sake to the flour. We add the vinegar and sake are added to create a crispier batter.
- Mix the batter but do not overmix. It’s okay to leave some lumps in the batter and the consistency should be thick like the batter for fritters. If the batter is too thick, add 1 Tbsp of ice water at a time. Keep the batter cold at all times.
- By now the oil should be close to 340–350ºF (170–180ºC). You can check the temperature with a thermometer or a chopstick. When you see small bubbles around the chopstick, the oil is ready for deep-frying. Tip: If you‘re new to deep-frying, please see my post on how to deep-fry food at home.
- Coat the shrimp with the batter and deep-fry until golden brown, about 2 minutes for medium-sized shrimp. Do not crowd the pot.
- Transfer the cooked shrimp to a wired rack or a plate lined with paper towels to drain the excess oil. Between batches, scoop up the crumbs in the oil as they will burn and turn the oil darker if left in the pot. Continue deep-frying the rest of the shrimp.
- Prepare a bowl with 2 Tbsp mentsuyu (concentrated noodle soup base). Dip both sides of shrimp in the mentsuyu and place back on the wire rack.
To Make the Tenmusu
- Transfer the hot cooked rice into a large bowl to cool down a bit. The rice needs to be warm (cool enough that you can touch it) when you make rice balls. Tip: If you‘d like to review my detailed instructions with step-by-step photos on how to shape rice balls, please see my Onigiri post.
- Prepare a small bowl of water and a small plate of Diamond Crystal kosher salt. Wet your hands in water and rub some salt on your hands (this is not just for the taste, but also to preserve the rice balls at room temperature).
- Scoop about 1 rice paddle of cooked rice into your hand.
- Make a small well in the center of the rice. In the well, place one piece of your 12 pieces Shrimp Tempura. I like my shrimp tail facing down, but you can show the tail side up if you like.
- Give one quick gentle squeeze to hold everything in one ball, just like how you make a snowball.
- Shape the rice ball into a triangle shape. Make a “triangle roof” with your right hand to create 3 corners of the rice ball. Gently press the rice ball with fingers and the heel of your hands. Never squeeze too tight.
- Cut each of the 3 sheets nori (dried laver seaweed) into 4 strips. The rough side should be facing up when you put the rice ball on top (the nice shiny side of the nori is facing outside).
- Wrap both sides of the nori toward the center and bend at the bottom. It looks like the rice ball is wearing a kimono (or v-neck shirt).
To Make the Tenmusu with Plastic Wrap (optional)
- Now, if you absolutely don’t want to shape your rice balls with your hands, place a sheet of plastic wrap over a small bowl, big enough so you can pull it out later. Put some rice on top and sprinkle with salt.
- Make a well in the center and place one shrimp tempura inside. Pull the plastic wrap from all sides.
- Start shaping the rice ball into a triangle shape, the same way as I described above. Unwrap the plastic wrap and put the nori around.
- If you prefer crispy nori and don’t plan on eating right away, you can keep the nori in an airtight bag and wrap around the rice when you’re ready to eat. Enjoy in several hours.
- It‘s best to enjoy the Tenmusu right away, or within a few hours. Rice gets hard and dry when it is refrigerated (although this works great for fried rice), so my only recommendation is to wrap it with plastic and then a thick kitchen towel to prevent it from becoming dry and hard.