The Battle of Kanagawa took place during the Sengoku period (16th century) of Japanese history, between Oda and Hà Âjà  forces.
Following the sudden death of Oda Nobunaga, the Hà Âjà  family soon took advantage of the situation and launched an attack on Oda clan territory.
Hojo Ujimasa's forces led by Ujinao and Ujikuni attack Oda Nobunaga's senior retainer, Takigawa Kazumasu, who had received territories after the defeat of Takeda Katsuyori the same year in 1582.
On the border between the Kà Âzuke and Musashi provinces, Kazumasu faced off against the Hà Âjà  forces at Kanegawa. Kazumasu had 18,000 troops, while the Hà Âjà  wielded 55,000, Kazumasu's defeat and retreated to Nagashima.
On July 7, as the Oda clan learned of the defeat of Takigawa Kazumasu by the Hà Âjà  clan at this battle, Toyotomi Hideyoshi sent a letter to Tokugawa Ieyasu to give him authorization to lead military operation to secure the provinces of Kai and Shinano from the Hà Âjà  and Uesugi clans.