Previous answer is
Mumei(unsigned) attributed as Hasebe.
I think the blade might be Hasebe Kuninobu.

Special feature : Hasebe Kunishige is well known sword maker as Masamune jitters.
Masamune jitters means 10 students of Masamune.
At that period, Hiromitsu and Akihiro and also Hasebe Kunishige are well known making Hitatsura hamon.
Generally the taihai in Nanbokucyo period, Nakago is small and wide and long
and also mitsumune style wakizashi. This Tanto is also small Nakago
and mitsumune style Tanto. Gunome midair with thick nioikuchi
and also very small nie is special feature of Hasebe school.
In Hasebe school, Hamon is gunome and yakisage from the top of
the blade to Munemachi area is Hasebe Kuninobu.
I think the blade must be Kuninobu.
Recently it is hard to look for Hasebe school regular size Tanto.

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Appraisal Quiz #257 (August 29th, 2013)
Who made this sword do you think ?
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Hints. ※The picture will be enlarged

Katana
Blade length : 73.48cm or 28.94inches.
Sori : 1.83cm or 0.72inches.
Mekugi: 3
Width at the hamachi : 2.85cm or 1.12inches.
Width at the Kissaki : 1.98cm or 0.78inches.
Kasane : 0.64cm or 0.25inches.
Weight of only blade:600g
Shape : Oosuriage Mumei blade. There are bohi engraved in the front and back.
Jitetsu :Koitame hada with komokume hada mixed. There are masa style flow in the jitetsu
and there are thick jinie attached. Clear jigane seen with faint utsuri.
Hamon : NIe base suguha. It is bright ha. The boshi is round ended.

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