Katana in Shirasaya, with Koshirae. (NBTHK Tokubetsu Hozon paper, NBTHK Koshu Tokubetsu Kicho Paper)
Signature : Oite Efu Chojusai Tsunatoshi gyonen 66 Okina Seitan
Bunkyu 3 nen 2 Gatsu hi Chyounsai Koretoshi Yaku.
explanation: The blade was made by Chounsai Tsunatoshi age 66 years by well forged.
February 1863 Chounsai Koretoshi who is a son of Tsunatoshi Yakiire(put the heated blade into the water)
The blade was polished by good polisher.
Habaki :gold foiled single habaki.
Blade length : 70.4cm or 27.71inches
Sori : 1.6cm or 0.63inches.
Mekugi : 1
Width at the hamachi : 3.16 cm or 1.24 inches.
Width at the Kissaki : 2.22cm or 0.87inches.
Kasane : 0.75 cm or 0.29 inches.
Era : Edo period Bunkyu era.
Shape : The blade is wide and thick and engraved Bo-hi on both sides of the blade.
Jitetsu :Masame had well grained with jinie attach beautiful masame texture.
Hamon : Niedeki suguha bright with ko ashi. Boshi is round shape hakikake style.
Special feature : Cyounsai Tsunatoshi was called Kato Hachiro and title was Cyounsai.
He was 3rd son of the Kato Izumi Kami Kunihide Yamagata prefecture who worked for Yamagata domain.
This sword is very rear Masame hada Jigane which is as same as Kiyondo who is a student of Kiyomaro.
Kiyondo came from Yamagata prefecture and studied Masame hada Jigane from Kunikane or others.
Probably Tsunatoshi was acquaintance with Kiyondo at that period and influenced a lot.
The texture is wonderful Masame hada.
Tsuba :On the round shape iron sukashi stub, kick flowers are engraved.
Fuchikashira :on the silver nanako plate, flowers are engraved.
Saya : black kawarinuri saya.
Menuki : On the syakudo plate, a dragon is engraved with gold color.
Historical background: Late Edo busy time.
NBTHK Tokubetsu Hozon paper
NBTHK Koshu Tokubetsu Kicho Paper
Aoi Art estimation paper : whole Oshigata.