Previous answer is
Mumei attribute as Aoe
Special feature : The Aoe School had been prospered at the lower reaches of the Takanashi river in Bichu province. This Katana shows distinctive characteristics of Aoe school though nakago has no signature because of Oosuriage. Generally Koitame hada well grained wrinkle Jigane.
At Muromachi period, Aoe school became went into decline in demand because of the long ages of war has been ended.
This blade is wonderful Jigane and nice active Hamon.
Appraisal Quiz #404 (September 10th, 2016)
Who made this sword do you think ?
Hints. ※The picture will be enlarged
Blade length :28.8 cm or 11.3 inches.
Sori : 0.3 cm or 0.1 inches.
Mekugi : 1
Width at the hamachi :2.57 cm or 0.10 inches.
Kasane : 0.49 cm or 0.2 inches.
Shape : The blade is longer size Tanto syape.
The blade is regular size Mitsu-mune style Tanto.
Jigane : Itame-hada well grained with Jinie attach and small Chikei work.
Hamon : Niedeki Gunome-midare from Hamachi area and then changes to Suguha with thick Nioikuchi.
Boshi is round shape.
1:Both sides of the Hamon are same shape.
2:Blade shape is Mitsumune style.
3:Mekugi-ana is larger than any other tanto forged by other swordsmith.
Please take a look to the shape of Nakago carefully.
Answer will be posted at next Appraisal Quiz.
(Please acknowledge not replying to mail about Appraisal Quiz by our convenience.)