When they were approaching the Toyotomi army, the Tokugawa army was defeated and a number of their troops were damaged badly in the Battle of Sanada-maru (December 3 and 4 [the old calendar]), the greatest battle in besieging Osaka Castle, which was triggered by the provocation of the Toyotomi side.
この接近時に豊臣方の挑発に乗って始められた、包囲戦における最大の戦いである真田丸の戦い（12月3日(旧暦)､4日）では、豊臣方が徳川軍を撃退、諸隊に大きな損害を与えた。