In this Japanese name, the family name is Tokugawa.
Tokugawa Nariatsu (徳川 斉敦 , December 16, 1780 – October 24, 1816) was a Japanese samurai who was the third head of the Hitotsubashi branch of the Tokugawa family.
The original article can be found at Tokugawa Nariatsu and the edit history here.