Sugata (Shape): Shinogi-zukuri with an Iori-mune. Wide mihaba and a thick kasane at the base, giving the blade a powerful and massive build. A shallow sori that curves toward an extended ō-kissaki, reflecting the bold construction widely seen during the Nanbokuchō period. Weight excluding the Habaki: 768 grams, giving a substantial feel in hand (see enlarged blade photographs).
Jitetsu (Forging Pattern): Itame-hada, mixed in places with large streaming grain and showing areas tending toward Masame hada. Fine Ji-nie is thickly applied overall, with places showing Yubashiri-like activity.
Horimono (Carvings): A Naginata-hi carved near the base, chiselled half way into the Nakago. The Shinogi-ji has been shaved off where a groove of bō-hi is carved.
Hamon (Temper Line): Nie-deki Suguha-based shallow Notare mixed with ko-gunome, including ko-gunome with a slanting tendencies. The boundary Ha-buchi is thickly covered with ko-Nie; ko-ashi appear frequently and isolating dots of Yō can be seen within the Hamon. In the Hira-ji, there are Yubashiri reminiscent of Tobiyaki.
Bōshi: On both Omote and Ura, the Bōshi is an irregular Midare-komi with a sweeping Hakikake finish, tending toward Yakizume-end.
Nakago: Ō-suriage, unsigned. Nakago-heel is horizontal Kiri. Two mekugi-ana. Yasurime is horizontal Kiri.

“Chiyozuru” 千代鶴 refers to swords forged by the Chiyozuru Kuniyasu school 千代鶴国安 active in Echizen Province from the mid to late Nanbokuchō period. Chiyozuru Kuniyasu 千代鶴国安 is said to have been the grandson of Rai Kunisue 来国末 of Yamashiro Province. According to tradition, Rai Kuniyasu 来国安 moved to Echizen around the Jōji era, becoming the founder of the Chiyozuru school 千代鶴. Kuniyasu 国安 is known to have signed both “Chiyozuru” 千代鶴 and “Rai Kuniyasu”来国安. Together with smiths such as Rai Munemitsu 来宗光 and Morihiro 守弘 the Chiyozuru group is also collectively referred to as Echizen Rai 越前来.

This sword has a strong and robust construction with a thick Kasane at the base, while the Shinogi-ji has been pared down to emphasize cutting-thgough ability. Its form follows the Nagamaki-zukuri style that became prevalent during the Nanbokuchō period, particularly around the Enbun and Jōji eras. The Jigane is slightly dark in tone, with a mixture of Itame and flowing hada, showing an outstanding grain. Fine Ji-nie is densely applied, with delicate Chikei appearing frequently. The Hamon consists of a wide Suguha-based shallow Notare mixed with ko-gunome and Saka-ashi and the Bōshi is irregular with sweeping Hakikake. While the blade clearly exhibits Rai-school characteristics of the Nanbokuchō period in both Ji and Ha, it also possesses a distinct northern provincial character, leading to its attribution as Chiyozuru 千代鶴.
Fitted with a solid silver single-layer Habaki. Preserved in a Shirasaya.
reference:
Masakuni Ishii, Kanzan Honma, Nihontō Meikan, Yūzankaku, 1975 (Shōwa 50)