This snack is a cake, which is made in shape of fish, with azuki sweet red bean paste inside of it. In the past, Japanese people only had “Imagawayaki”, which is a round-shape cake with the same filling. “Imagawayaki” are similar to Dorayaki (Doraemon’s favorite snack).
In Meiji-era, “Tai”, which means sea bream in Japanese, was a very expensive fish in Japan, and only eaten on the special events. It is known that one of the snack shops in Japan has changed the shape of “Imagawayaki” iron mold from circular to the shape of “Tai”. After that, these snacks became very popular in Japan, and they named it “Taiyaki”. “Yaki” meaning grilled or baked.
Nowadays, there are many types of the filling for these snacks. There is not only azuki sweet red bean paste, but chocolate filling, matcha (green tea) filling, and etc. Some shops even sell gyoza or a sausage filled taiyaki. Don’t worry if you still want to try the original one, because all the taiyaki shops always serve the original ones with azuki sweet read bean as well.
This is a “Wagashi” snack, which means it is one of the traditional Japanese confectioneries. The specialty of “Wagashi” is that most of them use azuki sweet red bean paste for the filling.
I recommend you to try the original “Taiyaki”, which is filled with azuki sweet red bean paste. It tastes very delicious. You can buy it at any festival held in Japan.