Oroshi hocho (Japanese: おろし包丁, "wholesale knife") and hancho hocho ( 半丁包丁, "half-tool knife") are extremely long, highly specialized knives used in Japan to fillet tuna and other large fish.

The oroshi hocho is a longer knife with a blade length of 150 cm (60 inches) in addition to a 30 cm (12 inch) handle. It can fillet a tuna in a single cut, although usually two to three people are needed to handle the knife and the tuna. The flexible blade is curved to the shape of the spine to

minimize the amount of meat remaining on the tuna chassis. The hancho hocho is the shorter blade with a length of around 100 cm (39 inches) in addition to the handle. The hancho hocho is also sometimes called a maguro kiri ( マグロ切, "tuna-cutter").

They are commonly found at wholesale fish markets in Japan, the largest of which is the Tsukiji fish market in Tokyo. They may be found at very large restaurants, but they are not used in a regular Japanese kitchen, unless there is a frequent need to fillet tuna with a weight of 200 kg (440 pounds) or more.

To those unfamiliar with Japanese knives they may be confused with Japanese swords. However, they are not a weapon but a tool, although they have been used as weapons by Yakuza.