Toyotomi Hideyori (豊臣 秀頼, born September 8, 1593, precise time and place of death debated) was the son and designated successor of Toyotomi Hideyoshi, the general who first united all of Japan. His mother, Yodo-dono, was the niece of Oda Nobunaga.
When Hideyoshi died in 1598, the five regents he had appointed to rule in Hideyori's place began jockeying amongst themselves for power. Tokugawa Ieyasu seized control in 1600, after his victory over the others at the Battle of Sekigahara. Hideyori's arranged marriage to Senhime, the seven-year-old granddaughter of Ieyasu, was designed to mitigate Toyotomi clan dissension and plotting. In this period, the eight-year-old boy practiced calligraphy with phrases wishing for peace throughout the world. However, Ieyasu continued to view the young Hideyori as a potential threat.
Tokugawa forces attacked Hideyori in the Siege of Osaka in the winter of 1614. The attack failed, but Hideyori was induced to sign a truce and dismantle the defenses of his stronghold at Osaka Castle.
In April 1615, Ieyasu received word that Toyotomi Hideyori was gathering even more troops than in the previous November, and that he was trying to stop the filling of the moat of Osaka Castle. Toyotomi forces (often called the Western Army) began to attack contingents of the Shogun's forces (the Eastern Army) near Osaka. On June 5, 1615, as Toyotomi's forces began to lose the battle, a smaller force led directly by Hideyori sallied forth from Osaka Castle too late, and was chased right back into the castle by the advancing enemies. There was no time to set up a proper defense of the castle, and it was soon set ablaze and pummeled by artillery fire. Hideyori and his mother committed seppuku, and the final major uprising against Tokugawa rule for another 250 or so years was put to an end. His widow remarried but later became a Buddhist nun.
According to James Murdoch's A History of Japan During The Century of Early Foreign Discourse, based heavily upon the works of many Japanese sources (the Nihon Shoki, Miyoshi-Ki, and many more) as well as heavily based on the writings of the Jesuits, their annual letters, the letters of Will Adams and the diaries of Adams' Dutch comrades, the events of Hideyori's death and the final fall of Osaka Castle were as such - Sanada Yukimura had been tactician of the climactic battle outside the gates of Osaka. Recognizing that they had a serious numerical disadvantage, they decided to attempt a tactic of inducing surprise and confusion in the Tokugawa camp. This was to be effected by first, Osaka captain Akashi Morishige getting behind the Tokugawa van, which would then be taken with Akashi's surprise attack, fall on Akashi, allowing Sanada with his troops and Mori Katsunaga, who was in charge of the Osaka Ronin, to fall into the Tokugawa front. When the confusion was to be at its height, Hideyori would have marched out of Osaka castle with his home troops and would in theory be the final blow to the Tokugawa.