Siege of Kawagoe Castle

What Happened

The Siege of Kawagoe Castle (河越城の戦い, Kawagoe-jō no tatakai) ran from 1545 into 1546, ending on 19 May 1546. It was fought over Kawagoe Castle, at the coordinates 35.9244° N, 139.4914° E, in the town of Kawagoe. The castle was held by the Later Hōjō clan; the attacking coalition was led by Uesugi Tomosada of the Ogigayatsu branch of the Uesugi clan.

Tomosada was joined by Uesugi Norimasa of the Yamanouchi branch, a more powerful relative who held the post of Kantō Kanrei (関東管領, Kantō kanrei), the shōgun's deputy in the Kantō region. The coalition also included Ashikaga Haruuji, the Kantō kubō (関東公方, Kantō kubō) based at Koga, and a host of anti-Hōjō daimyō from across the Kantō.

The siege ended in failure for the attackers. The relief of the castle is remembered as one of the Three Surprise Attacks of Japan, a traditional grouping of night attacks in Japanese military history. The battle is associated with Tōmyō-ji Temple.

Background

The siege belongs to the Sengoku period (戦国時代, Sengoku jidai), the century and a half of near-continuous warfare among regional warlords that ran through the Muromachi period (1336–1573). In the Kantō, the plain around modern Tokyo, two great houses had been locked in conflict: the Uesugi, an old and prestigious warrior family with branches at Ogigayatsu and Yamanouchi, and the Later Hōjō, a newer power that had built its strength in Odawara.

Kawagoe Castle mattered because it anchored the northern approach to the Kantō. The Later Hōjō had taken it from the Uesugi, and recovering it would have restored Uesugi standing in the region. By 1545 the Uesugi were able to assemble an unusually broad coalition against the Hōjō: both branches of their own house, the Kantō kubō Ashikaga Haruuji, and a range of daimyō who feared Hōjō expansion. The campaign fell in Tenbun 天文 year 14, the fourteenth year of an era name that ran from 1532 to 1555.

Why It Mattered

The failure of the siege was decisive for the balance of power in the Kantō. The Uesugi had committed both branches of the family and the authority of the Kantō Kanrei and the Kantō kubō to a single objective, and lost. The Later Hōjō kept Kawagoe and went on to consolidate their hold on the region.

The battle is remembered in Japanese military tradition as one of the Three Surprise Attacks of Japan, alongside famous night attacks of earlier centuries. That reputation rests on the manner of the castle's relief rather than on the length of the siege. The outcome also shaped the careers of the men involved: Uesugi Tomosada did not survive the campaign, and the Ogigayatsu line's fortunes never recovered.

The Name in Japanese

The Japanese name is 河越城の戦い, read in kana as かわごえじょうのたたかい and romanised as Kawagoe-jō no tatakai.

Breaking it down:

• 河 — read here as kawa. The kanji means "river". It is the same character used in the name of the Kawa river, from which Kawagoe takes part of its name.
• 越 — read here as goe, a voiced form of koe. The kanji means "to cross over" or "to exceed". Together, 河越 (Kawagoe) means roughly "river crossing".
• 城 — read here as jō, the Sino-Japanese reading. The kanji means "castle". Note that the same character has a native Japanese reading, shiro, also meaning "castle"; jō is the reading used in compound names.
• の — written in hiragana, not kanji. This is the possessive particle, linking "Kawagoe Castle" to "battle". It corresponds to the English "of" or the apostrophe-s.
• 戦 — read here as tatakai, a native Japanese reading. The kanji means "war" or "battle". In compounds it is often read sen, as in 戦国 (Sengoku, "warring states"), but here it stands alone with its kun reading.
• い — hiragana, completing the word 戦い (tatakai), the noun form of the verb 戦う (tatakau), "to fight".

So the whole name parses as "Kawagoe Castle's battle". Japanese battle names of this type follow a fixed pattern: place name, then 城 (jō, castle), then の (no, of), then 戦い (tatakai, battle). Recognising the pattern lets a reader parse hundreds of similar entries — 大阪城の戦い, 小田原城の戦い, and so on — by identifying the place name at the front.

Key Figures

Uesugi Tomosada (上杉朝定) — head of the Ogigayatsu branch of the Uesugi clan and the principal instigator of the attack on Kawagoe Castle. He did not survive the campaign.

Uesugi Norimasa (上杉憲政) — head of the Yamanouchi branch of the Uesugi and holder of the office of Kantō Kanrei, the shōgun's deputy in the Kantō region. He joined Tomosada's campaign, bringing the weight of his office and his branch's military strength.

Ashikaga Haruuji (足利晴氏) — the Kantō kubō, the Ashikaga shogunate's representative in the Kantō, based at Koga. He joined the coalition against the Later Hōjō.

The Later Hōjō clan (後北条氏, Go-Hōjō-shi) — the defenders of Kawagoe Castle and the rising power of the Kantō, based at Odawara. Their retention of the castle ended the Uesugi challenge.