Nigiri sushi sold at street stalls during the Edo period is said to have been roughly the size of a small rice ball today, weighing about 50 to 70 grams per piece. According to historical records such as Morisada Manko (守貞漫稿), eating just two or three pieces was considered a sufficient light meal. Eventually, complaints that the sushi was “too large and difficult to eat” led to it being halved in size and served two pieces at a time, though there are several theories about why this change occurred. This adjustment allowed diners to enjoy a greater variety of toppings in a single visit.
The weight of shari and toppings is actually decided by each restaurant; there is no industry standard.
So how did this weight come to be? The answer lies in a unit of rice that has been deeply ingrained in Japanese life.
In Japan, the smallest unit for measuring rice is called ichigo (一合), which equals 150 grams (180 cc). This is also considered a standard portion for one meal, and household rice cookers often have markings based on multiples of this unit. Cooking an ichigo yields approximately 300 to 330 grams of cooked rice. While actual consumption varies depending on age and gender, the concept of “ichigo equals one meal” has been established for centuries. This unit has been passed down not only in households but also in sushi restaurants, where chefs use it to calculate the required cooking volume and determine how much rice to prepare at once.
This unit is also scalable: ten times ichigo equals ishou (一升). Until about 30 years ago, it was common for sushi restaurants to cook nishou (二升) of rice at a time, and commercial rice cookers sized for this purpose were available. Today, chefs typically cook rice according to the number of reservations, often calculating one serving as a little over ichigo.
Looking further back, during the post-war rationing period, there was a “commissioned processing system” where rationed rice could be brought to sushi shops for processing. Bringing ichigo of rice to a sushi shop would get you seven pieces of nigiri sushi and one nori roll, equivalent to about ten pieces of nigiri. Working backward from this system, it is estimated that the rice weight per piece in the post-war period was approximately 30 to 33 grams.
This weight served as a standard benchmark for some time after the war. Gradually, alongside changes in food culture, this standard also shifted. Responding to customer requests to enjoy more sushi toppings, the amount of rice per piece gradually decreased. By the late Showa period, it was around 20 grams. Today, in the Reiwa era, the mainstream is 10–15 grams per piece in central Tokyo sushi restaurants and 15–20 grams in regional areas.
Sushi chefs carefully consider the thickness of the fish, its fat content, and the temperature and humidity of the rice to achieve the “balance that tastes best in one bite.” In recent years, partly due to rising ingredient costs, there has been a trend toward reducing the rice even further. Some pieces now weigh less than 10 grams, though it is said that reducing them any more makes it difficult to discern subtle differences in flavor, especially in white fish.
The weight of the rice is not merely a matter of quantity; it represents the “art of the bite,” shaped by 200 years of Japanese food culture and aesthetic sensibility.