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. It took place on the 26th day of the 4th month of the Keichō era.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.