Previous answer is
　 Mumei(Sekishu Dewa Sadatsuna) 　

Special feature: The founder of Sekishu Sadatsuna is Naotsuna and
Sadatsuna was a son of Naotsuna. His style called "Hokkoku Mono".
The Jigane is black and Hadatachi, many interesting changes.

==============================================
Appraisal Quiz #597 (July 11th, 2020)
Who made this sword do you think ?
==============================================

Blade length : 68.9 cm or 27.12 inches.
Sori : 1.9 cm or 0.74 inches.
Mekugi : 2
Width at the hamachi : 3.05 cm or 1.20 inches.
Width at the Kissaki : 1.94 cm or 0.76 inches.
Kasane : 0.66 cm or 0.25 inches.
Shape : Regular width and thickness Katana.
The shape is elegant old style.
Jigane : Itame Hada and Mokume Hada with Jinie attach.
Hamon : Ko Nie Deki, Suguha base with Ko-Ashi.
The Nioikuchi is thick. The Habuchi is soft. The Hamon is graceful.
In Ha, there are fine Sunagashi and Kinsuji.
Boshi is Notare and Hakikake style.

Hints. ※The picture will be enlarged

================================================

Answer will be posted at next Appraisal Quiz.

================================================

(Please acknowledge not replying to mail about Appraisal Quiz by our convenience.)