The Battle of Kashii (樫井の戦い) was the very first battle of the Summer Campaign of the 1615 Siege of Osaka, near the beginning of the Edo period in Japan. As the Shogun's Eastern Army prepared to renew the siege begun the previous winter, the Ōsaka garrison sallied forth, ambushing 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 shogun. The attackers were led by Ōno Harunaga, Hanawa Naoyuki, and Okabe Noritsuna.