In 1853, the 12th shogun, Ieyoshi TOKUGAWA died and his fourth son, Iesada TOKUGAWA ascended to be the 13th Shogun, but was in poor health and had no hope to have a son.
嘉永6年（1853年）に第12代将軍徳川家慶が死去し、第13代将軍に家慶の四男・徳川家定が就任するが、病弱で男子を儲ける見込みが無かった。