A Ko-Mihara Katana (古三原)

This katana is an o-suriage mumei work attributed by the NBTHK to the Ko-Mihara school of Bingo province, present-day eastern Hiroshima. The Mihara school rose toward the end of the Kamakura period and flourished into the Muromachi era; works from the late Kamakura through the Nanbokuchô periods are collectively known as Ko-Mihara. The lineage began with the founder Masaie and continued through his son Masahiro, and the strong Yamato character of their work reflects both Bingo’s reputation for fine iron and the migration of Yamato smiths into the region, drawn by the temple and shrine estates that linked the province to the Kinai capital.

The blade speaks plainly of that pedigree. A beautifully forged itame is blended with mokume and flowing masame, threaded throughout by a river of chikei and accompanied by ji-nie in a faintly dark steel. Over this runs a wide, bright suguha with deep nioi and ko-nie, animated by kinsuji and sweeping sunagashi, with occasional kuichigai-ba where the nioiguchi splits over a noticeable distance – a hallmark of the Yamato tradition. The boshi is a healthy komaru and the kissaki itself is exceptionally well preserved. The NBTHK captured it perfectly in the jûyô tôken zufu, describing a dignified form with a sense of strength, its minute edge activity offering refined taste and quiet beauty.

As an o-suriage blade the original signature was lost when the nakago was shortened, most probably during the Keichô era to bring a treasured Nanbokuchô tachi into line with Tokugawa dress regulations. Tanobe Michihiro (Tanzan-sensei) confirmed the attribution in a sayagaki of June 2012, judging the work healthy and fine and, within the lineage, particularly reminiscent of Masahiro or Masanobu. Ranked Jô-saku in the Fujishiro system, this is a classic Ko-Mihara beauty – not a showy Bizen blade but a sword of quiet confidence that rewards the collector who takes the time to sit with it.