Katsuobushi is smoked, dried and fermented bonito fish. It is one of the most essential ingredients in the Japanese kitchen. It is mostly used to make 'dashi' broth, which forms the base for many sauces, stocks and Umami flavor in well-known Japanese dishes. Traditionally Katsuobushi is used in blocks and shaved using a wooden grater box. 

Katsuobushi originated a few thousand years B.C, but the elaborate preparation process that is still used by some makers today, dates back to the 16th century. Raw bonito fillets are gutted, sliced and simmered in water for about an hour. After that, fat, scales and bones are removed, leaving a soft and clean fillet that is smoked on wood to try and develop an even more complex flavor. Next, they are sundried and exposed to fermentation to further reduce moisture. This process is repeated up to four times! 

The final Katsuobushi product is only 20% the volume of the original fillet! 

Traditionally, the 'honkarebushi' are then shaved using a wooden grater, in order to deliver the best, authentic Katsuobushi shavings. Nowadays, however, many people buy cheap, pre-shaved Katsuobushi flakes at the supermarket, which are heavily altered and industrialized.