Ko-Gassan, works from the Gassan school dating to the Muromachi period, are some of more scarcely seen and desirable Japanese swords. This blade is a long 70.3cm daito which (per the accompanying Aoi Bijutsu certificate) dates to the mid Muromachi period. The workmanship is textbook, including a somewhat naturalistic ayasugi hada which is relaxed in areas, unlike the rigid ayasugi seen in shinshinto times. The hamon is a perfect suguha witg fine kinsuji. The ji features a very vivid utsuri, which can be seen in the oshigata. There is a nijimei of ‘Gassan’ but I do not believe it is authentic. The blade is healthy and completely flawless. It has a well made silver foil habaki and top quality shirasaya with bamboo.