33°39′20″N 130°26′44″E / 33.65556°N 130.44556°E / 33.65556; 130.44556

Battle of Kashii
Part of the Siege of Osaka
At the remains of Kashii battlefield in Sennan, Osaka prefecture, Japan.
Date May 26, 1615 Location Kashii, near Wakayama Castle, Kii Province, Japan Result Toyotomi defeat and withdrawal
Belligerents
Tokugawa shogunate	Toyotomi clan
Commanders and leaders
Asano Nagaakira	Ōno Harunaga Ban Naoyuki † Okabe Noritsuna
Strength
5,000	3,000

The Battle of Kashii (樫井の戦い) was the first battle of the Summer Campaign of the Siege of Osaka, fought in Japan in 1615, near the beginning of the Edo period. It took place on the 26th day of the 4th month of the Keichō era.

As the Shōgun's Eastern Army prepared to renew the siege begun the previous winter, the Ōsaka garrison sallied and ambushed Tokugawa forces in a number of skirmishes and sieges. In the battle of Kashii, a contingent of forces loyal to Toyotomi Hideyori, lord of Ōsaka, attempted to besiege Wakayama Castle, which was controlled by Asano Nagaakira, an ally of the shōgun. The attackers were led by Ōno Harunaga, Ban Naoyuki, and Okabe Noritsuna.

Tachibana Muneshige, who served as military advisor of the second shogun, Tokugawa Hidetada,^[1] had correctly predicted the movements of Toyotomi's general Ono Harufusa's troops, and guided Hidetada's troops.^[2]

Asano's garrison realized that their attackers were far from support or reinforcements, and met them in battle at Kashii, near Wakayama. Okabe and Ban were killed in the battle, and Ōno was consequently forced to retreat to Ōsaka.

• Turnbull, Stephen (1998). 'The Samurai Sourcebook'. London: Cassell & Co.