Talk:Higekiri/@comment-42.113.192.29-20160102143812/@comment-667468-20160102154242

One of the acceptable versions of Higekiri and Hizamaru's origin depicts Higekiri as a sword crafted by Kokaji Munechika (a.k.a. Sanjou Munechika, the same smith as Mikazuki) for the Japanese emperor.

So the short answer to your question would (likely) be Sanjou.