Toyotomi Hideyori, the son and successor of Toyotomi Hideyoshi, was in Osaka Castle with 113,000 men. His opponent was Tokugawa Ieyasu, de facto ruler of all Japan after his victory in the Battle of Sekigahara, with an army about 194,000 men. They fought several battles, starting with one in 1614 at the mouth of the Kizugawa (the Summer Siege), and ending when Hideyori's forces attacked those of the Tokugawa at the Battle of Tennoji (the Winter Siege), in 1615.
The article is originally from OpenHistory.