Answer previous answer was Mumei (unsigned) Ko-mihara school.
Kinzogan-mei signature: Nakagawa Saheita Te-nite tachi.
Temae nite Waki-ge otosu, (16th NBTHK Juyo Token)

Special feature : Mihara school had been prospered from late Kamakura
to late Muromachi period in Bingo province present Okayama prefecture.
The representative swordsmiths were Masaie and Masahiro.
Especially the works of last Kamakura period to Nambokucho period
are called Ko-Mihara, and are distinguished from the later period.
Rising above the times, the school had been influenced by the Yamato School.

This blade passed the 16th NBTHK Juyo Token.
Especially Chirimen-hada Jitetsu is fantastic, and it looks Rai school
or Aoe school on the surface.
And this blade is the best quality in the Ko-mihara blades.
And there is Kinzogan-mei signature of Nakagawa Saheita, it is very precious !!

Nakagawa Saheita was ace of Tameshi-giri.(cutting test) in early Edo period.
He was called Nakagawa Saheita Shigeyoshi, and he battled at
Siege of Osaka (1614 and 1615).
He received family estate in 1631 when his father’s retire.
He was a ace of Tani school of Tameshi-giri, and his name was written
on book of Tani school.

 

 

 

 

 

Hint:

Blade length : 27.1 cm or 10.66 inches.
Sori : 0.2 cm or 0.07 inches.
Mekugi: 1
Width at the hamachi : 2.44 cm or 0.96 inches.
Kasane : 0.45 cm or 0.17 inches.
Shape : Regular sized Tanto with Saki-zori and Mitsu-mine.
On the Sashi-omote side, Ken-maki-Ryu dragon is engraved in the Bo-hi.
On the Sashi-ura side, Dokko and Suken sword are engraved in the Bo-hi.
Jitetsu : Itame hada works very well, covered in much Chikei.
And there are Yubashiri.
Hamon : Ko-nie based, Gunome midare change to big Gunome midare.
Boshi is round shape.
There are Sunagashi and small Kinsuji and Inazuma in Ha.

Special features : This swordsmith mainly made wider and thicker blades than this Tanto.