Siege of Kasagi

What Happened

On 4 October 1331, forces loyal to the Kamakura shogunate attacked a fortified Buddhist temple called Kasagi-dera, perched on Mount Kasagi (笠置山, Kasagiyama) south-east of Kyoto. The temple sheltered Emperor Go-Daigo, who had withdrawn there with the imperial regalia and was gathering an army. The fighting lasted through the month and ended on 30 October 1331 with the temple burned.

The assault came at night. Hōjō commanders Suyama Yoshitaka and Komiyama Jirō led troops up the cliffs surrounding the fortress, a route the defenders had considered impassable, and set the complex alight. Kasagi-dera burned.

The Emperor escaped the burning temple and fled. He was captured later, but not at Kasagi, and not by these commanders. The siege itself was a shogunate victory; the war it opened was not.

Background

The Kamakura shogunate had governed Japan since 1185, but real power within it had long since passed from the shogun to the Hōjō clan, who held the office of regent and directed the government from Kamakura. By the 1320s the arrangement was strained: the shogunate had mismanaged the aftermath of the Mongol invasions, rewarding loyal warriors poorly, and it faced a determined opponent in Emperor Go-Daigo.

Go-Daigo intended to rule in fact as well as in name. In 1331 he left Kyoto and established himself at Kasagi-dera, a temple on a mountain whose cliffs made it defensible, and began secretly raising an army. He had also moved the imperial regalia — the sacred objects that legitimised an emperor's claim to the throne — into the temple for safekeeping. The shogunate learned of the plan and moved to crush it before it grew.

The campaign that followed is known as the Genkō War (元弘の乱, Genkō no ran), named for the era in which it began. The siege of Kasagi was one of its first battles.

Why It Mattered

The shogunate won at Kasagi, but the victory settled nothing. Go-Daigo escaped the burning temple, and his cause survived him: within two years the shogunate's own generals had turned against it, Kamakura fell, and the Kamakura period — nearly 150 years of Hōjō-dominated government — came to an end in 1333.

Kasagi therefore marks the opening of the war that destroyed the shogunate, not the suppression of a revolt. The temple itself did not survive long either. It was rebuilt in 1381, destroyed by fire again less than twenty years later, and today only a few of its buildings remain on the mountain.

The Name in Japanese

The battle is called 笠置山の戦い, read かさぎやまのたたかい (Kasagiyama no tatakai).

Breaking it down:

• 笠 — read kasa here. A broad conical hat worn for protection from rain or sun, the kind associated with travellers and farmers. The mountain is said to be named for its shape.
• 置 — read gi here (the two kanji together form kasagi). To place, set down, or put. In this compound it carries the sense of something set or positioned.
• 山 — read yama. Mountain. It appears in the place name Kasagiyama and also in the word san when the same character is read in Sino-Japanese contexts.
• の — read no. The possessive and linking particle, written in kana rather than kanji. It joins Kasagiyama to tatakai, so the phrase means "the battle of Kasagiyama".
• 戦 — read tataka here, from tatakau, to fight. Battle or combat.
• い — read i, the kana ending that completes the verb form tatakai, a noun meaning "a fight" or "a battle".

So the whole name is a straightforward description: the battle of Mount Kasagi. Note that the mountain name is written with three kanji, 笠置山, while the battle name adds the particle の and the noun 戦い.

Key Figures

Emperor Go-Daigo (後醍醐天皇, Go-Daigo Tennō) — the emperor who withdrew to Kasagi-dera in 1331, moved the imperial regalia there, and raised an army against the shogunate. He escaped the burning temple during the siege.

Suyama Yoshitaka — Hōjō commander who led the night assault on Kasagi-dera, climbing the cliffs with his troops.

Komiyama Jirō — Hōjō commander who led forces alongside Suyama Yoshitaka in the same attack.

The Hōjō clan — the family that dominated the Kamakura shogunate as hereditary regents, and the target of Go-Daigo's revolt.