Impact behaviour of the Japanese sword

The Japanese sword is a weapon peculiar to Japan. The present study is concerned with the joint between tohshin (blade) and tsuka (hilt) of the Japanese sword. Only one mekugitake (retaining peg made of bamboo) with about 5mm in diameter holds the tang in the hilt. However a slender mekugi might not be broken, even in the case of violent sword-fighting. This fact has been historically demonstrated in many battles by Japanese swords. In this study it is examined theoretically and experimentally from the viewpoint of impact engineering why a mekugi used in Tachi and Katana may not be broken. As a result, it is found that such a strong force as breaking a mekugi-take does not act on it, because of the location of mekugiana (a hole for mekugi) in the tang, which has been made in the Japanese sword by following the traditional code of sword-smiths.