The Battle of Nagashino took place in 1575 near Nagashino Castle on the plain of Shitaragahara in the Mikawa province of Japan. The castle had been under siege by Takeda Katsuyori since the 17th of June; Okudaira Sadamasa, a Tokugawa vassal, commanded the defending force. The castle was under attack because it threatened Takeda's supply lines. Both Tokugawa Ieyasu and Oda Nobunaga sent troops to alleviate the siege and Takeda Katsuyori was defeated. The victory of Oda's Western-style tactics and firearms over Takeda's cavalry charge is often cited as a turning point in Japanese warfare; many cite it as the first 'modern' Japanese battle. In fact, the cavalry charge had been introduced only a generation earlier by Takeda's father, Takeda Shingen. Furthermore, firearms had already been used in other battles.