[RobT]

JeffS,

Thanks for following up on this. I really suspected that the characters are Japanese but I didn’t know for sure. It’s pretty interesting that the translation of the Chinese characters (“special”) is so close to the Japanese kanji for “specially made”.
However, it’s rather odd to see a Japanese made blade that isn’t symmetrically ground. So the questions now are: Who was the maker that used the diamond logo?, Why did the maker consider the dagger to be specially made?, For what culture was it made?

Sincerely,
RobT