[ Feature ]
Form : Shinogi-zukuri. Mihaba is relatively wide. Shallow sori attached. Chu-kissaki extended form.
Nakago : O-suri-age. Saki is kiri. Yasurimes are kiri. Tow holes.
Engraving : Both on front omote and back ura, there is bo-hi groove.
Jigane : Itame-hada with some changes. Grained pattern comes to be appeared, hada-tatasu state. Jinie attached. Chikei appeared.
Hamon : Ko-notare, gunomes mixed. Ashis appeared. Nie attached well. Sunagashis and kin-suji appeared frequently. Yu-bashiri appeared as well.
Boushi : It shows frequent haki-kake state, then it shows nie-kuzure pattern.

[ Highlight ] This work has a slightly wider body with a large polished appearance, itame grain forged with a wavy blade pattern with an even pattern as the main tone, with strong boiling of the base blade, sunagashi and gold streaks, and a strong Soshuden style. The jigane is slightly darkened, the base has a strong skin and the blade is richly worked. Naotsuna I is listed as one of the ten Masamune swordsmiths (Rai Kunitsugu, Hasebe Kunishige, Shizu Saburo Kaneuji, Kaneshige, Go Yoshihiro, Norishige, Sekishu Naotsuna, Osafune Kanemitsu, Osafune Nagayoshi and Sa monji). There are several swordsmiths with the same name, the first being Kemmu, the second Eiwa and the third Oei period.　

[ Conditions ] Excellent.