The siege of Osaka was a series of battles undertaken by the Japanese Tokugawa shogunate against the Toyotomi clan, and ending in that clan's destruction. Divided into two stages, the winter campaign and the summer campaign, it lasted from 1614 to 1615. The siege put an end to the last major armed opposition to the establishment of the Tokugawa shogunate. The end of the conflict is sometimes called the Genna Armistice , because the era name was changed from Keichō to Genna immediately following the siege.