Ninpei Era

Ninpei (also read Ninpyō) was the era name in use from its proclamation in the first month of Kyūan 7 (1151) until the change to Kyūju in the tenth month of Ninpei 4 (1154), during the reign of Emperor Konoe. Sword texts place Yukinobu (行信), traditionally regarded as founder of the Senjuin school — said to be the oldest of the five Yamato schools — around this time (another tradition dates him to the Chōshō era, 1132–1135), so the period is discussed as the formative stage of the Yamato tradition.

Origins of the Senjuin School

The Senjuin school is said to have been a group of swordsmiths in clerical status attached to Tōdai-ji in Nara. They forged in the Senju valley at the foot of Mount Wakakusa, and the school's name is said to come from the Senjuin (Senju-dō), a hall there enshrining the Thousand-armed Kannon. Besides Yukinobu, Shigehiro is also named as a founder, but no signed work by either survives. The oldest Senjuin work is called "Ko-Senjuin"; no signed examples exist, and the surviving pieces are unsigned blades attributed on the basis of their style.

Characteristics of the Yamato Tradition

The Yamato tradition is characterized by a high shinogi with a wide shinogi-ji, jigane in which masame (straight grain) stands out, and a hamon based on suguha. Ko-Senjuin blades are described as having strong koshi-zori with firm fumbari and a small kissaki of slightly ikubi form, itame grain flowing with masame, and a narrow suguha-like hamon mixed with ko-midare. It is a sober, practical style, in contrast to the flamboyant chōji-midare later seen in Bizen work such as that of the Ichimonji school.

Temples and Swordsmiths

Yamato swordsmiths are said to have been attached to the great Nara temples such as Tōdai-ji and Kōfuku-ji, and to have developed in response to their warrior monks' demand for weapons. The Senjuin school is likewise regarded as a lineage of smiths serving Tōdai-ji; together with the later Tegai, Taima, Shikkake and Hōshō schools it makes up the five Yamato schools.