Korefuji (是藤, lit. "Right Wisteria") is the sword Mitsurugi used on his first quest for Soul Edge. Later, when he lost to firearms in an imperial court tournament, it was confiscated by his lord. Several years later, that lord died, and Korefuji went missing. Even now, after countless battles, it remains as sharp as ever.
The first katana Mitsurugi used. It was a common katana (in the old Soul Archive, it's referred to as a Tachi). After he lost to the Tanegashima in a duel in front of his lord, he became dissatisfied with it and cast it aside, replacing it with Shishi-Oh.