The Ko-Bizen school
- Ko-Bizen is the name of the oldest swordsmiths of Bizen. The Japanese Wikipedia relates that tradition attributes its founding to Tomonari, summoned by Emperor Ichijō in the Eien era (987–989), but that the work preserved runs from the end of the Heian to the middle of the Kamakura.
- Among its names, those with the most blades are Masatsune and Tomonari.
- In neighbouring Bitchū, the Ko-Aoe had swordsmiths with the same names, Masatsune among them, and it is sometimes hard to decide whether a blade belongs to one school or the other.
One or several Masatsune
- The Japanese Wikipedia gives him as a swordsmith of Bizen of the end of the Heian, of unknown dates, and the one of the Ko-Bizen with the most signed work preserved.
- It has been said since long ago that he wrote the character “tsune” (恒, tsune) of his signature in seven ways. That variety and some blades with traits of the beginning of the Kamakura suggest several swordsmiths with the same name.
- The official records of his tachi say so too: that of the Kyūshū National Museum speaks of several Masatsune because of the differences in style and signature, and one from the Tokugawa Art Museum recalls that there are tachi with his signature that look like the beginning of the Kamakura. That same record notes that he is held to be a man of the end of the Heian.
- The NBTHK’s Japanese Sword Museum dates its Important Cultural Property tachi to the beginning of the Kamakura and says that in those years there were, it is thought, several swordsmiths with the same signature.
- Another record from the Tokugawa Art Museum, that of its National Treasure tachi, says that of all the Masatsune the signature of that blade is the most archaic.
The tradition: the Nawakiri
Tradition attributes to him the sword Nawakiri Masatsune (縄切正恒, Nawakiri Masatsune), the one Sasaki Takatsuna is said to have carried at the battle of the Uji River in 1184. It is a story, not a document. The sources consulted do not say where that sword is, if it survives.