Keiichiro RYU wrote a book called "Imposter: Ieyasu TOKUGAWA" in which he proposed that Ieyasu died in the Battle of Sekigahara in 1600 and that an imposter took over at that point.
隆慶一郎は家康が1600年の関ヶ原の戦いの際に死去し、その後は影武者が代役として立てられたという設定で小説「影武者徳川家康」を著している。