Katsuobushi (鰹節 or かつおぶし), also known as okaka (おかか) is the dried, fermented, and smoked skipjack tuna. Young bonito has a similar color and texture and is sometimes used as a cheaper substitute for skipjack tuna. Katsuobushi’s distinct umami flavor comes from its high inosinic acid content.
Traditionally, large chunks of katsuobushi (you can buy here) were kept at hand and shaved when needed with an instrument called a katsuobushi kezuriki, similar to a wood plane. However, katsuobushi today is typically found in bags of small pink-brown shavings.
- Hanakatsuo (Katsuo Kezuribushi) (花鰹; はなかつお): Smaller, thinner shavings and used as a flavoring and topping for many Japanese dishes, such as okonomiyaki. You can purchase good quality Hana Katsuo here (ships internationally).
- Kezurikatsuo (削り鰹; けずりかつお): Larger, thicker shavings and used to make dashi stock.