Tokugawa Ieyasu (徳川家康) died on June 1, 1616, at Sunpu Castle in Shizuoka, at the age of seventy-three. He had been the most patient conqueror in Japanese history — waiting through decades of civil war, surviving defeats that would have destroyed lesser men, finally seizing power after the Battle of Sekigahara in 1600. By the time he died, Japan was at peace for the first time in a century. He had one more instruction to give.

His will specified that after one year, his spirit was to be moved from 久能山東照宮 (Kunozan Toshogu) — the mountainside shrine in Shizuoka where his remains were first placed — to a new shrine at 日光 (Nikko), in the mountains of Tochigi Prefecture, roughly 140 kilometers north of Edo. There he was to be enshrined as a god. He had already arranged the divine title he wished to receive: 東照大権現 (Tosho Daigongen) — the East-Illuminating Great Avatar.

In the spring of 1617, the procession set out. Approximately 1,200 priests, samurai warriors, Buddhist monks, Shinto ritualists, court musicians, and ceremonial attendants accompanied the sacred palanquin through mountain passes and forested valleys. His son, the second shogun 徳川秀忠 (Tokugawa Hidetada), thirty-eight years old, presided over the enshrinement ceremony when the procession arrived at Nikko. The court formally bestowed the divine title. Ieyasu the warlord became Ieyasu the god.

This was not piety. It was policy. Ieyasu had watched 豊臣秀吉 (Toyotomi Hideyoshi) attempt to found a dynasty through a human heir — his son Hideyori — and fail catastrophically within years of Hideyoshi's death. Ieyasu's solution was different: don't leave your legacy in the hands of a child who can be outmaneuvered. Become something that cannot be killed a second time. Make loyalty to the Tokugawa shogunate an act of religious devotion rather than merely political obedience.

The strategy worked with remarkable precision. For the next 265 years, the shogun's annual pilgrimage to Nikko was one of the greatest displays of power and piety in the realm. To criticize the Tokugawa government was, in effect, to insult 神君 (shinkun) — the divine lord — which was as dangerous as it sounds. Any reform that touched the fundamental structure of the shogunate risked being characterized as sacrilege.

The shrine that received Ieyasu's spirit in 1617 was relatively modest. The apotheosis of Ieyasu was a multigenerational project. It was his grandson, the third shogun 徳川家光 (Tokugawa Iemitsu), who rebuilt 日光東照宮 (Nikko Toshogu) in 1636 into the staggering complex of gold leaf, lacquer, and intricate carvings that stands today. More than 500 carved figures decorate the 陽明門 (Yomeimon) gate alone — including, deliberately, one inverted pillar, because perfect beauty was thought to attract the jealousy of the gods.

Among the shrine's most famous images is the 三猿 (sanzaru) carving on the sacred horse stable — the three monkeys who hear no evil, see no evil, and speak no evil. It is one of the most recognized images in Japanese culture, and it lives at the shrine of a deified shogun.

A detail that complicates the legend: some scholars argue that Ieyasu's actual physical remains never left 久能山 (Kunozan) in Shizuoka. What traveled to Nikko may have been symbolic relics rather than the body itself. The shrine at Nikko neither confirms nor denies this. The question of whether the god is truly present is, perhaps, beside the point. The shrine did its work regardless.

Every year on May 17 and 18, the annual spring festival at 日光東照宮 (Nikko Toshogu) re-enacts the original 1617 procession with 1,000 participants in full period armor. The ceremony is called the 百物揃千人行列 (Hyakumono-Zoroe Sennin Gyoretsu) — the Thousand-Person Procession of a Hundred Things. Four centuries later, the dead man's march to godhood is still performed on schedule.