Mikawa (三河国; -no kuni) is an old province in the area that today forms the eastern half of Aichi prefecture. Mikawa bordered on Owari, Mino, Shinano, and Totomi provinces.
Even today, Mikawa is used to refer to the eastern portion of Aichi, including such cities as Toyohashi, Okazaki, and Toyota.
Mikawa was the original fief of the Shogun Tokugawa Ieyasu before he gained control of Kanto. Okazaki was the principal castle town of Mikawa, although Yoshida Castle, near Toyohashi, was also a major fief at times. Mikawa is famous in Japan for its fireworks manufacturing most of Japan's fireworks. So the Shogun could maintain security, Mikawa was the only area allowed to produce gunpowder which lead to the fireworks industry. The annual Okazaki fireworks are one of the best in Japan.
