Hello Epahler,
The inscription on the sword is 山田敏周 (Yamada Toshichika), which is the name of a swordsmith working in one of the Seki sword factories during WW2. You can see the 関 (Seki) seal in between the two peg holes. This shows it was inspected, and passed, by the quality control inspectors of Seki. The smith's real name was Yamada Toshizō, and his "artists" name was Toshichika.