When I first came to Japan, I lived in a Tokyo shared house with a small kitchen which made cooking difficult. Most of my meals were either eaten out or bought already made at the local grocery store. Japan had a lot of interesting foods, and I wanted to try them all. Not being able yet to read Japanese, I one day bought what looked like seared tuna. The fish, which was in fact katsuo, was served with green onions and tasted quite fishy. In order to avoid this mistake, I made a point to tell tuna and katsuo apart from that day on. Years later, on a visit to Kochi, my friends reintroduced me to katsuo tataki. I tried it with some reticence but to my surprise it was delicious. Why was Kochi’s katsuo so delicious when Tokyo’s was not?
Katsuo tataki, or seared skipjack tuna, is related to the larger tuna family. Reaching up to one meter in length, it is smaller than most tunas. Katsuo migrate in large shoals that can reach fifty thousand fish. Although they have decreased in numbers, they can still be fished in relatively large quantities on the coast of Kochi, the southern most prefecture of the island of Shikoku. The shoals follow the northward warm current called Kuroshio that provides them with an abundance of food. They are traditionally fished in Kochi using the ippon-zuri method or single line fishing. This technique is not only sustainable; it also yields the best tasting fish as netting increases the stress of the fish. Historically, fish that could not be consumed locally were shipped in the form of dried katsuo bushi to other parts of the country. Today, it is shipped across Japan but be aware it will not be as fresh.
Katsuo tataki can be seared on a gas stove yet Kochi resident prefer it warayaki which means grilled over a straw fire. The short and intense burst of flames create a lightly burn crisp outside where most of the fat is located. Unlike other kinds of sashimi, the fish is sliced vertically into thick pieces instead of the traditional angled pulling motion. Kochi residents have different opinions when it comes to seasoning, some prefer coarse salt, others tare while others like shoyu. It is also served on a bed of thinly sliced raw onions, green onion and garlic (I have yet to hear of another place in Japan that uses raw garlic in its cuisine). Finally, katsuo tataki is accompanied in Kochi with ponzu, yuzu citrus juice or special tataki sauce. One might think that this might deter from the taste of the fish but strong flavors blend well with the seared fish creating a burst of flavor with every bite.
The legend says that Kochi fishermen wary of raw fish would sprinkle sea salt (not being able to afford shoyu) on the freshly caught katsuo filet and sear it straight on the beach using driftwood and pine needles. Thus, was born katsuo tataki. Yet, I remain skeptical of these legends as reality is often more complicated than a good story. Katsuo tataki is primarily eaten fresh and frequently in Kochi, hence, people discriminate between good and bad quality. Most people have their favorite shops or even sometimes prepare it at home. In Kochi, katsuo tataki is often shared on large shared platters called sawachi. Not only does Kochi uses the best fish and the most elaborate preparation, it truly has developed a culture of katsuo tataki. Although it can be found across Japan, katsuo tataki is at its peak in the same region that created a culture around it.