The Toshogu Shrine is the main attraction of Nikko. The Shinto shrine is dedicated to the kami (spirit) of Ieyasu (d. 1616), who founded the Tokugawa Shogunate, a military dynasty that ruled Japan from 1603 to 1867.

To create a worthy shrine for the shogun, 15,000 craftsman worked for two years, using 2.5 million sheets of gold leaf. The enshrinement of Ieyasu's spirit is reenacted twice each year in the Procession of the Thousand Warriors.

Unlike most Shinto shrines, characterized by minimalist architecture that blends into its surroundings, Toshogu is a riot of color, gold, and carvings, with birds and flowers, dancing maidens, and sages following one another around the buildings. Some visitors find the shrine awe-inspiring and beautiful; others are repelled by the gaudiness. In contrast to the exuberance of the shrine, Ieyasu's mausoleum itself is relatively simple and austere.

One of the most famous elements of Toshogu is the Sacred Stable, where a white imperial horse is kept (a gift of New Zealand). The stable's fame derives from the original carving depicting the three wise monkeys, "Hear no evil, Speak no evil, See no evil." Other famous carvings at Toshogu include a sleeping cat and an odd rendering of an elephant by an artist who had apparently never seen one.

Although a Shinto shrine, Toshogo contains several Buddhist elements. Next to the entrance gate is a five-story pagoda in red and gold, and beyond it is the formal entryway flanked with the Two Deva Kings. A Buddhist library with over 7,000 scrolls of sacred texts is contained in a revolving case, which can be turned in order to effect the equivalent of praying all the texts.