Katana in Shirasaya(NBTHK Hozon Paper)
Signature: Mumei (Kohoki)
The blade was polished.
HAbaki: Kinkise single foiled habaki
Blade length : 69cm or 27.18inches.
Sori : 2cm or 0.79inches.
Width at the hamachi : 2.77cm or 1.09inches.
Width at the Kissaki : 1.88cm or 0.74inches.
Kasane : 0.51cm or 0.2inches.
Era : Late Heian Period.
Shape : It is round shape nakago with regular width and thickness.
It had deep curves though. The kissaki part is slightly turn down
towards the tip, it shows from the appearance that it is an aged sword.
Jitetsu : Itame hada well grained with mixture of bigger pattern wood pattern(ooitamehada) mix and
the hada is moist. Shinogiji is also ooitame hada well grained jigane.
Hamon : NIe base suguha with mixture of gunome midare. In the temper line
there is sunagashi, kinsuji actively placed.
The temper line(hamon) is soft with complex pattern. koashi is soft end.
Special feature : Kohouki school was active from late Heian period.
Following the Yasutsuna, the head, Sadatsuna, Masakake were some of
the most successful smithes of this school. Unlike the kobizenmono, jigane is
loose and large grained hada(O-hada) and dark steel surface(jigane) with some chikei.
This piece again, has ohada with dark chikei spots placed in the jigane.
Shinogiji is as well have similar hada.
There are many activates in the ha and jigane steel is wonderful.
This ancient Kohouki has unique characteristic which turns out as an elegant figure.
It is hardly believable from the jigane and hamon that it is 820 years old katana.
The dignity of the blade could also been seen from the shape.
Because there are no engraved lines(hi) on the ha,
you could observe well the jigane. If it is repolished, it will look much better.
Historical background: Late Heian period year 1184 Battle of Ichinotani- The genii
and the Taira fought at SettsukokujFukuhara which is now Suma, Hyogo.
The Taira family was defeated by Genji family (MInamoto no Noriyori and MInamoto no Yoshitsune.)
NBTHK Hozon Paper
Aoi Art estimation paper : whole Oshigata.