I don't know kanji but that is a left-handed deba.
I did a little research on your kanji letters. The first two are "betsu da" meaning "specially forged" "
別 打".
The last two are "
友 沢" which is tomo sawa / tomozawa / tomizawa, which may be a person, company or place name.
The complex one in the middle looks like
隷, "rei" which means :"slave" as a standalone word. I may not have gotten that one right, it is a complicated symbol.
I don't speak or read Japanese, that's just from doing some Google searching of the characters.