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Concurrent: Fall of Odawara
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Siege of Oshi
Oshi Castle
Campaign: Odawara Campaign
Date: 1590
Place: Oshi, Sagami Province
Outcome: Toyotomi victory

Toyotomi Toyotomi Shogunate

Hojo Hojo


Mitsunari Ishida
Sakon Shima
Kiyomasa Kato
Sakon Shima
Masanori Fukushima
Keiji Maeda
Yukimura Sanada

Ujiyasu Hojo
Ujinaga Narita
Nagachika Narita
Kai Narita







The Siege of Oshi Castle was the final step in the process of taking down the last of the opposing clans in Japan by the Toyotomi, whose leader Hideyoshi Hashiba had all but united the land. The attack, led by Mitsunari Ishida, succeeded, but the Toyotomi suffered heavy losses before the Hojo surrendered.


Toyotomi strategist Mitsunari Ishida planned to attack Oshi Castle, a Hojo stronghold, while Hideyoshi Hashiba and the main body of the Toyotomi Coalition attacked the larger Odawara Castle, the main Hojo fortress and the capital of Sagami. Mitsunari had 23,000 troops, facing a mere 3,000 Hojo troops under Ujinaga Narita, a trusted retainer and vassal of the Hojo clan; and his daughter Lady Kai, a fearsome female samurai.

The Hojo began by whittling down the defenses around the Toyotomi main camp, their forces advancing. The Toyotomi forces punched back, but not before suffering heavy losses, many of them killed by Kotaro Fuma, who had infiltrated their lines. The Toyotomi troops were suddenly cut down to size by a water attack by Lady Kai, who destroyed the embankments to flood the enemy. The Toyotomi were put in even more trouble when Ujiyasu Hojo arrived with a large force, but Ujiyasu's death turned the tide of battle. The Toyotomi troops pushed back the enemy and the garrison of Oshi Castle surrendered, ironically after the fall of Odawara Castle, which had a much larger garrison.