[P]rior to about the 1920s, no self-respecting Japanese person would eat any kind of tuna at all if they could possibly avoid it. Tuna was so despised in Japan that all tuna species qualified for an official term of disparagement: gezakana, or “inferior fish.” In the old days in Japan, if you had no choice but to eat tuna you’d do everything you could to get rid of the bloody metallic taste of the fresh red meat. One trick was to bury the tuna in the ground for four days so that the muscle would actually ferment, which led to tuna being called by the nickname shibi—literally, “four days.”