Board Thread:Wiki Discussion/@comment-3467648-20140517182108/@comment-24095889-20140603185509

"Gackpo has a samurai aesthetic: the VOCALOID is clad in a Jinbaori, a kind of  kimono which was used as a battle surcoat, with parts of Japanese armor, and carries a  katana which is named “Music katana, Miburi” (楽刀・美振 / Gakutou Miburi). The patterns on its blade make musical sounds when it is swung down.  The sword existed because producers wanted a link to a musical instrument, there were no objections to the use of a weapon."

That's what's currently on his page so I'd go with the main points of that..