【Reading】こあゆずし

【English Name】Ko-ayu zushi (small sweetfish sushi)

Koayu-zushi is a type of traditional sushi made with small ayu (sweetfish), roughly 10 cm in body length. It is particularly known as a local dish that has long been made around Lake Biwa in Shiga Prefecture.

Lake Biwa is home to a unique small ayu (koayu) that spends its entire life within the lake, and koayu-zushi is most often made using the narezushi technique, in which the koayu is salted and then pickled together with cooked rice for lactic-acid fermentation. Narezushi is regarded as one of the oldest forms of sushi in Japan, and koayu-zushi is a representative example that conveys that tradition to the present day.

It is characterized by the distinctive sourness from fermentation and the flavor unique to ayu, and the fermentation period can extend from several weeks to several months. In modern times it is also sometimes served as pressed sushi or whole-fish sushi (sugata-zushi) using vinegared rice, and the production method varies by region and shop.

The koayu fishing season on Lake Biwa peaks from early summer through summer, and the fish is often prepared during this period. As a dish symbolizing the food culture of Shiga, it is sometimes ranked alongside funa-zushi (crucian carp sushi).