There is no secret, I only know that Konka likes to eat eggplant and miso, especially in his later years. He spoke highly of eggplant, saying that it is "the food of men who dominate the world".

Also, at that time, ordinary Japanese didn't eat much animal meat on land, because they thought that eating intestines would rot, and they basically ate aquatic animals such as fish, shrimp and crabs. I don't know whether a "noble" like Tokugawa eats or not.

Secondly, I think Tokugawa's longevity is largely due to his mentality. Tokugawa can laugh at the end, but it is actually a word of "forbearance", but it is not forbearance, but relaxation, waiting quietly, seizing every opportunity while waiting, thinking more and growing old quickly.