Why are Japanese samurai called swordsmen when they clearly use knives?

Japanese Dao (にほんとぅ, Japanese head), a general term for Japanese traditional Dao by foreigners, is called flat-broken-section compound dark-light-textured Dao. According to the shape and size, it can be divided into Taidao, broadsword, rib gap (rib finger) and short knife. Among them, the knife mentioned by the Japanese refers to the shape of the avenue. Japanese knives in a broad sense also include long rolls, razors, swords, guns and so on. Since ancient times, Japanese knives have been famous for their beautiful shapes and weapons. Many famous knives are collected as art treasures, which contain the meaning of samurai soul. In the forging process, the ratio of Japanese hilt to blade is generally 1:4, and the hilt is held with both hands. Japanese samurai swords in Japanese mountain cities chop powerfully, and their bending degree is controlled in "object impact" (also called "inside the object"), that is, below the front tip 16.7mm, where the cutting force is the largest, which conforms to the mechanical principle. The back of the knife is called "building" or "ridge" to resist attacks. There are four kinds: Ping, An, San and Wan.