"Shimesaba" refers to a dish made by marinating mackerel fillets and then marinating them again in vinegar. Mackerel is a fish with a distinct strong odor, tender flesh, and a tendency to spoil easily. Therefore, marinating it in vinegar not only enhances the flavor but also improves its texture and prolongs its shelf life. In Eastern Japan, it is commonly known as "Shimesaba," while in Western Japan, it is referred to as "Kizushi" (a general term for vinegar-marinated fish). Shimesaba is often sliced and consumed raw like sashimi or used as an ingredient in sushi. The representative sushi made with shimesaba is "Sabazushi" (mackerel sushi). Sabazushi involves placing thick slices of marinated mackerel directly on top of sushi rice and rolling it into a cylindrical shape using a sheet of nori (seaweed). On the other hand, "Battera" is made by thinly slicing shimesaba, placing it in a rectangular mold with sushi rice, and pressing it to create a sushi block.