The siege began on 19 November, when Ieyasu led 3,000 men across the Kizu River, destroying the fort there. A week later, he attacked the village of Imafuku with 1,500 men, against a defending force of 600. With the aid of a squad wielding arquebuses, the shogunate forces claimed another victory. Several more small forts and villages were attacked before the siege of Osaka Castle itself began on 4 December. The Sanada-maru was an earthwork barbican defended by Sanada Yukimura and 7,000 men, on behalf of the Toyotomi. The Shogun's armies were repeatedly repelled, and Sanada and his men launched a number of attacks against the siege lines, breaking through thrice. Ieyasu then resorted to artillery  as well as men to dig under the walls. On 22 January the Winter Siege was ended, with Toyotomi Hideyori pledging to not rise in rebellion. He also allowed Ieyasu to tear down the walls of the outer layer of defenses, and fill in the outer moat of Osaka Castle.

Based on the above article, answer a question. How many more men did Ieyasu's forces have compared to the defending forces when they attacked Imafuku?
900