How to Katsuobushi is made:

1. The fish is filleted into three, which is called “kame bushi (turtle block)” from its shape. In case of a fillet being big enough, cut it into two pieces. In this case, two pieces has individual names. The upper piece on each side is known as obushi (“male” block), and the lower as mebushi (“female” block). Each piece is also called honbushi.
2. The fish is simmered to set the proteins, before being cooled.
3. The fish is soaked in water then the scales, skin and bones are removed by hand.
4. The pieces of fish are then repeatedly smoke-dried and cooled down. This completes the process for arabushi.
5. The surface of the dried blocks is shaved to remove the tar that has build up during smoking.
6. After inoculation, the blocks are left to dry. This is repeated up to three times to make karebushi. If the process is repead more than four times, the superior quality block created is known as honkarebushi.