In September 1561, Uesugi Kenshin left his Kasugayama fortress with 18,000 warriors, determined to destroy Takeda Shingen. He left some of his forces at Zenkoji, but took up a position on Saijoyama, a mountain to the west of, and looking down upon, Shingen's Kaizu castle.
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Kōsaka Danjo Masanobu left Kaizu with 8,000 men, advancing up Saijoyama under cover of night, intending to drive Kenshin's army down to the plain where Takeda Shingen would be waiting with another 8,000 men ... However, whether via spies in Kaizu or scouts looking down from Saijoyama, Kenshin guessed Shingen's intentions, and led his own men down to the plain. Kenshin descended from Saijoyama by its western flanks. Instead of fleeing Kosaka's dawn attack, Uesugi Kenshin's army crept down the mountain, quietly using bits of cloth to deaden the noise of the horse's hooves. With the beginning of dawn, Shingen's men found Kenshin's army ready to charge at them