Iemitsu, who was Ieyasu's grandson and the third Tokugawa shogun (1603 1651), undertook the building of Toshogu.
Ieyasu's grandsoon was 80 years younger than him.
mnli hypothesis: Ieyasu's grandsoon was 80 years younger than him. premise: Iemitsu, who was Ieyasu's grandson and the third Tokugawa shogun (1603 1651), undertook the building of Toshogu.