Offering an ubu Muromachi period katana in koshirae with current NTHK kanteisho to the Dewa Ko-Gassan swordsmith Munetsugu. The jihada is a beautiful ayasugi-hada, typical of what you would see from the Ko-Gassan school. The blade has a suguha-based hamon activities which flow with the jihada. The blade is in late Edo period buke-zukuri koshirae, with shakudo fuchigashira and menuki, and an Edo period iron tsuba. The saya does need repairs (a replacement kojiri and to be reglued). While the NTHK kanteisho noted the blade as being Tensho (late Muromachi), the only Ko-Gassan Munetsugu I see documented is from the early Muromachi period, circa Oei. His bio is below, courtesy of Markus Sesko.

MUNETSUGU (宗次), Ōei (応永, 1394-1428), Dewa – “Gassan Munetsugu” (月山宗次), Gassan school