In 1636, the third shogun Tokugawa Iemitsu undertook the 'Great Kan'ei Reconstruction' of Nikko Toshogu. He mobilized a cumulative total of 4.54 million craftsmen to complete the current magnificent halls. Virtually everything we see at Toshogu today — the Yomeimon Gate's 508 carvings, the Sleeping Cat — is the work of Iemitsu. It was a grand project expressing deep devotion to his grandfather Ieyasu and the intent to demonstrate Tokugawa shogunal authority to all of Japan.

Ernest Satow was a British diplomat stationed in Japan from the late Edo to Meiji periods who left detailed research on the shrines and temples of Nikko. In 1875, Satow authored 'A Handbook for Travellers in Central & Northern Japan,' introducing Toshogu and other Nikko temples to the Western world. This work promoted foreign tourist visits to Nikko and was instrumental in establishing Nikko as an internationally known destination.