The Battle of Nagashino took place in 1575 near Nagashino Castle on the plain of Shitarabara in the Mikawa Province of Japan. Takeda Katsuyori attacked the castle when Okudaira Sadamasa rejoined the Tokugawa, and when his original plot with Oga Yashiro for taking Okazaki Castle, the capital of Mikawa, was discovered. Katsuyori attacked the castle on June 16, using Takeda gold miners to tunnel under the walls, rafts to ferry samurai across the rivers, and siege towers. On June 22 the siege became a blockade complete with palisades and cables strewn across the river. The defenders then set Torii Suneemon to get help. He reached Okazaki, where Ieyasu and Nobunaga promised help. Conveying that message back to the castle, Torri was captured, and hung on a cross before the castle walls. Ieyasu and Nobunaga sent troops to assist Sadamasa and break the siege, and their combined forces defeated Katsuyori. Nobunaga's skillful use of firearms to defeat Takeda's cavalry tactics is often cited as a turning point in Japanese warfare; many cite it as the first "modern" Japanese battle.