Gifu Castle
Since the Tokugawa army departed from Edo, it could only take two roads, both of which converged on Gifu Castle. Ieyasu marched on Gifu while Ishida Mitsunari was delayed at Fushimi Castle. This fortress was a halfway point between Osaka and Kyoto and was controlled by the Tokugawa ally Torii Mototada. Ishida could not risk leaving a force that could attack his rear, so he marched on it. It took him ten days to capture Fushimi, and in that time Gifu Castle had fallen. This forced Ishida Mitsunari to retreat southward in the rain. The rain was relevant in that the bulk of both armies were equipped with matchlock rifles ("tanegashima"), which required dry gunpowder to fire.