Kobayakawa was one of the daimyō who had been courted by Tokugawa. Even though he had agreed to defect to the Tokugawa side, in the actual battle he was hesitant and remained neutral. As the battle grew more intense, Ieyasu finally ordered his arquebuses to fire at Kobayakawa's position on Mount Matsuo to force a choice. At that point Kobayakawa joined the battle as a member of the Eastern Army. His forces charged Ōtani's position, which did not end well for Kobayakawa. Ōtani's forces had dry gunpowder, so they opened fire on the turncoats, making the charge of 16,000 men mostly ineffective. However, he was already engaging forces under the command of Tōdō Takatora, Kyōgoku Takatsugu, and Oda Yūraku when Kobayakawa charged. At this point, the buffer Ōtani established was outnumbered. Seeing this, Western Army generals Wakisaka Yasuharu, Ogawa Suketada, Akaza Naoyasu, and Kutsuki Mototsuna switched sides, turning the tide of battle.