Tachi signed Sanetsune

Sanetsune was a swordsmith active in Bizen Province (present-day eastern Okayama Prefecture) during the Heian period, associated with the Ko-Bizen school considered the oldest lineage in Japanese sword history. Alongside Masatsune and Tomonari, his work exemplifies the dignified style of Heian-period tachi.

This tachi measures 89.4 cm in blade length, with a curvature of 3.9 cm, a base width of 3.5 cm, a tip width of 2.2 cm, and a kissaki length of 3.5 cm. Its thick spine and wide body give it a grand, imposing form — unusually large for a late Heian tachi, and often ranked alongside the famed Okanehira as a masterpiece of the era.

After Tokugawa Ieyasu's death, Kunozan Toshogu Shrine was built at Kunozan (in present-day Shizuoka City) in accordance with his will. The second shogun, Tokugawa Hidetada, is said to have dedicated this tachi to the shrine during its 1617 relocation ceremony, making it one of the earliest sword offerings to the shrine and a central treasure of its collection.

The blade was designated a National Treasure on June 9, 1951. It is often called "the yokozuna among National Treasure tachi," and together with the Important Cultural Property blade Sohaya no Tsurugi, forms the twin pillars of Kunozan Toshogu's sword collection.

The sword remains in the possession of Kunozan Toshogu Shrine and is displayed on a rotating basis at the Kunozan Toshogu Museum, together with its accompanying itomaki-tachi mounting, featuring a gold nashiji lacquer scabbard decorated with paulownia crests and shakudo nanako-ground gold fittings.