These days, one of the quickest and most popular methods for stocking a video game with a cast of attractive anime-style characters is to pick a class of item and anthropomorphize the heck out of it.
The method of hardening the steel that is so typical of Japanese swords was first used in 6th century.
In the first stage of its development Japan imported iron tools and weaponry from the continent and continental craftmen immigrated in Japan. Soon after the Japanese begun to forge and manufacture their own blades.
Oldest metal swords on record in Japan are the two that were sent as a present to queen Himiko from China during Wei-dynasty in 240 a. We do know that in the 5th century steel swords were already made in Japan.
Rather than issue certificates, the expert providing the authentication would sign his name and other information to the blade, on the unpolished part hidden by the handle when the handle is attached.
to get the very edge of the blade in focus, but again, working with both the camera and the blade held by hand, it proved to be too challenging.