AS21441-Katana: Mumei (Sekishu Naotsuna)

Katana in Shirasaya(NBTHK Hozon Token )(Consignment Sale)
Signature :　Mumei (Sekishu Naotsuna)
無銘（石州直綱）　初代　　

(We divide 4 sections for each sword as Saijyo saku, Jyo-jyo saku Jyo saku and regular saku)
This sword belongs to Jyo Jyo Saku ranking.
The blade was polished.
Habaki :　silver single habaki.
Blade length : 77.3 cm or 30.43 inches.
Sori :2.58 cm or 1.01 inches.
Mekugi : 3
Width at the hamachi : 2.97 cm or 1.16 inches.
Width at the Kissaki : 1.77 cm or 0.69 inches.
Kasane : 0.47 cm or 0.18 inches.
The weight of the sword 655grams.
Era : Nanbokucho period around Kakei era(1387-1389)
Shape : O-Suriage Mumei, regular width and thickness Katana with deep Sori, Chu-Kissaki.
There are Futasuji Hi on both side of the blade.
Jigane : Itame Hada well grained and Hadadatsu.
The Jigane is blackish. There are faint Utsuri appears.
Hamon : The series of large and small Gunome Midare with many Ashi, thick Nie, and also Togari Gunome Midare.
In the Ha, there are a lot of Kinsuji and Sunagashi.
Reminiscent of the flow of water Sunagashi and Kinsuji
It is a powerful work called Masamune Juttetsu.

Special feature: The first generation Sekishu Naotsuna is a child of Moritsuna and is known as one of the Masamune Juttetsu, commonly known as Kuemon, and is known locally as Dewa Masamune. The place of residence is Shimane Prefecture.
The blade is a nice shape with a beautiful Jigane. The Hamon fully demonstrates the characteristics of the Sekishu Naotsuna in the late Kamakura period.

From Aoi Art: It is said to be the oldest year of Naotsuna, Eiwa 2nd year 1376.
He was a swordsmith in Iwami and continued for several generations with the first generation as Kenmu era(1334-1336). The 1st generation is Kenmu era, the 2nd is Eiwa, the 3rd is Ouei. From the shape, this blade was made around the end of the Kamakura period.

NBTHK Hozon Token
Aoi Art estimation paper: whole Oshigata.