The Battle of Dewa was the Battle of Sekigahara fought in the North, in which Uesugi Kagekatsu was defeated and forced to submit to Tokugawa Ieyasu.

Uesugi Kagekatsu raised an army of 50,000 to move against Tokugawa Ieyasu, but lost Shiroishi in a siege to the combined armies of Date Masamune and Mogami Yoshiaki. Afterwards, Mogami sent a letter to Kagekatsu, suggesting that he become a vassal of Tokugawa. Kagekatsu refused and ordered his chief vassal Naoe Kanetsugu to attack the Mogami territory of Dewa. Kanetsugu led a force of more than 20,000 in an invasion of Mogami's territory, capturing Hosoya Castle. However, though he surrounded Hasedou Castle, it stood firm with the aid of Yamagata Castle.

Taking advantage of Uesugi's superiority of numbers, Onodera Yoshimichi also invaded Mogami territory. Surrounded, Yoshiaki send a request for aid to his nephew Date Masamune. 500 cavalry from Date a few days later held the battle to a stalemate. However, when news of the defeat of the western forces in the Battle of Sekigahara reached Uesugi and Mogami, Mogami gave chase to Uesugi's retreat in sudden reversal, resulting in fierce battles around Hasedou Castle. Uesugi lost more than 1,500, Mogami around 600.