Here are some more pictures of the Toshogu Shrines in Nikko. Here is the link to the Nikko Tourist Association: http://www.nikko-jp.org/english/chuzenji/index.html
The Okusha Hoto was originally a wooden building when first constructed in 1622, but was remodeled into a stone structure in 1641. The bronze pagoda, which we see now, is a 1683 reconstruction, built after an earthquake destroyed the stone building. In order to keep dry the remains of Tokugawa Ieyasu, enshrined underground beneath the pagoda, the stone bedded floor is sloped to drain outward and the joints of the stone blocks constituting the stepped foundation are sealed with lead to block the penetration of rainwater.