The spotted Sardine (Gizzard Shad) commonly referred to as herring, is most commonly referred to in Japanese as Kohada, and is fished off the central shores of Japan.

While usually labeled kohada on sushi menus, this fish actually has a number of names, each corresponding to the age. Youngest Gizzard Shad are known as Shinko. As the fish matures, its name becomes kohada, then Nakazumi, and finally Konoshiro and a Konoshiro, a fully grown gizzard shade.

The rarest size is the smallest, and the medium more common and the largest most common, seen below. Interestingly, the price of gizzard shad has an inverse relationship to its age. Shinko commands a much higher price than older shad and is often ¥20,000+ per kilo. This decrease in value is due to the fact that as the fish ages it becomes increasingly bony.

You rarely find the the smallest (shinko) in sushi bars, and for most Japanese aficionados they wouldn’t even be familiar with smallest size.

Although the main fishing season is fall and winter, these fish (konoshiro or Kohada) are a part of most sushi chef’s repertoire and it can be found all year round.

The fish below is a comparison between Kohada (left) and Shinko (right).

-up to 5 cm: shinko (smallest)
-up to 10 cm: kohada (medium)
-over 15 cm: konoshiro (large)