* Image is for illustrative purposes only.Ko-Gassan
古月山
Description
Overview
The Gassan smiths were a lineage based at the sacred peak of Mount Gassan, one of the Dewa Sanzan in Dewa Province (present-day Yamagata Prefecture). Tradition holds that the school was founded by the legendary Oniōmaru, who is said to have begun forging on the sacred grounds of Mount Gassan. The school flourished from the Kamakura through the Nanboku-chō and Muromachi periods alongside the development of Shugendō practice on the Dewa Sanzan. To distinguish this koto-period lineage from the later Gassan school revived in Osaka during the Edo period (Sadakazu, Sadakatsu, and others), this earlier line is conventionally called Ko-Gassan ("old Gassan").
Ayasugi Hada
The defining feature of Gassan work is ayasugi hada (also called Gassan hada), a distinctive forging pattern in which the grain of the steel appears in large, wave-like bands resembling cedar boarding. This pattern is unique to the Gassan school and is not seen in other traditions.
Peak and Decline
The Gassan smiths are said to have reached their peak during the Nanboku-chō period, and forging continued through the end of the Muromachi period alongside the prosperity of Dewa Sanzan Shugendō. However, once the Edo period began and the Dewa Sanzan became purely religious institutions without military force, the Gassan school as a community of swordsmiths declined rapidly.
Revival under Gassan Sadakichi
The koto-period Gassan lineage lapsed during the Edo period, but in its final years a member of the Gassan line, Yahachirō Sadakichi, moved from Yamagata via Edo to Yariyachō in Osaka, where he revived the ancestral ayasugi forging technique and established the Osaka Gassan school. From Sadakichi's adopted son, Gassan Sadakazu I, the Gassan line continued unbroken into the modern and contemporary eras.
Standing
The koto-period Gassan smiths (Ko-Gassan), as the Dewa lineage that originated the distinctive ayasugi forging, occupy an important place in discussions of regional character in Japanese swords. Their technique was carried forward through the Edo-period revival into today's Gassan school.