Previous answer is
Bichu Kokubu Ju Asae Otsuki Saburobee Kunishige (Ko-Mizuta)
Special feature: Bicchu Kuni Ayabe Totsuki Saburo bee Kunishige was made around late Muromachi period which is called Ko Mizuta (old Mizuta)
The sword has Zokumyo iri not simple Mizuta Kunishige.
This kind of Zokumyo blade was made for high ranking samurai or Daimyo.
It is an ancestor of Kunishige Mizuta and is quite different from the works of the Edo period.
It becomes a blade hamon tand becomes aranie We highly recommend works with dignified common names(zokumyo iri)
The Koshirae is a wonderful work of Higo.The sword passed NBTHK Tokubetsu hoson Token.
Appraisal Quiz #631 (March 13th, 2020)
Who made this sword do you think ?
Blade length : 71.4 cm or 28.11 inches.
Sori : 2.1 cm or 0.82 inches.
Mekugi : 3
Width at the hamachi : 3.26 cm or 1.28 inches.
Width at the Kissaki : 2.57 cm or 1.01 inches.
Kasane : 0.77 cm or 0.30 inches.
Shape : Wide and thick Katana with Sori, nice shape Katana. The kissaki is O-Kissaki.
There are Bo-Hi on both side of the blade.
Jitetsu : Itame Hada, Nagare and Hadadatsu with Jinie attach.
Hamon : Nie Deki, Omote side, Gunome Midare and Ko-Choji Midare.
Ura side, Ko-Notare and Gunome Midare. There are many Ashi, Yo, Sunagashi, and Kinsuji.