The origin of the Tegai 手掻 school dates back to the Kamakura period (1185–1333). The Tegai School is one of the 5 schools of the Yamato Den 大和, located opposite the Tengai Mon, the western gate of the Todaiji Temple in Nara. The founder of this Tegai lineage is Kanenaga 包永, a blacksmith of the late 13^th century, many blacksmiths of this school inherited kanji ’Kane‘ in this form.
The Shodai Kanezane 包真 (1^st gen) was a student of the 3^rd generation Kanenaga around 1361, and the blade shown here is the 6^th generation Kanezane 包真.

This blade from the 6^th generation Kanezane 包真 dates from the late Muromachi, circa 1575. This date is important because it was at the Battle of Nagashino, where Oda Nobunaga and Ieyasu Tokugawa defeated Katsuyori Takeda (Son of Takeda Shingen). This battle, with the use of firearms by Nobunaga, marked a turning point in medieval Japanese military strategies. It is often seen as Japan’s first ‘modern’ battle.

The Yamato tradition blades are quite rare compared to the 4 other traditions, more modern and prolific like Bizen and Mino. Another explanation is that the blacksmiths of Yamato produced for the temples and warrior monks, enemies of the powerful warlords, which did not help their development.
This tradition influenced many schools in Bizen and also gave birth to the Mino Shizu school with Kaneuji 包氏 who was a student of Masamune and settled in Mino. He then adopted Kanji Kane in this form 兼, which most blacksmiths in Mino would take.

This Koto blade from the Tegai School of Yamato tradition is therefore particularly rare.