The Battle of Oshi Castle: The Day a Twenty-Year-Old Female Warrior Held Out Against the Water Attack

In June 1590 (Tenshō 18), at Oshi Castle in Musashi Province. Ishida Mitsunari's army of over 20,000 besieged the castle, and was damming the surrounding rivers to attempt a water attack.

The castellan Narita Ujinaga was shut up in Odawara Castle, and among those defending Oshi in his absence was his eldest daughter Kaihime.

She was around twenty.

Oshi was a castle built in a water-country zone; the moats and marshes wove together into a natural water castle.

Even when Ishida Mitsunari dammed the surrounding rivers, the water did not flow as intended into the castle.

The epithet 'floating castle of Oshi' arose from the figure of this castle enduring the water attack.

The Narita-ki and the Kanhasshū Kosen-roku transmit that Kaihime took part in the siege defense in armed capacity.

As her father's substitute, she is said to have led female warriors to defend a part of the castle.

Cases of women taking up arms in siege defense were exceptional for the time; a family style of female education in the Narita house is inferred.

Oshi Castle endured the water attack, and only opened its gates after the fall of Odawara in July.

After the surrender, Kaihime's valor and beauty are transmitted by the Narita-ki to have reached Hideyoshi, and Hideyoshi took her as consort.

The epithet 'greatest beauty of the Kantō' is said to have arisen at this time, but contains elements of Edo-period narrative-making.

The Battle of Oshi Castle was one siege within the great campaign of Toyotomi Hideyoshi's Odawara expedition.

Kaihime's armed participation is now an object of modern women's history research as a rare case of a woman of the late Sengoku becoming the principal bearer of a siege defense.

The Oshi Castle ruins in Gyōda City, Saitama Prefecture, are preserved today as the principal transmission site of the Oshi Castle campaign.