The story begins with an illegitimate child. Hoshina Masayuki was the natural son of Tokugawa Hidetada, the second Tokugawa shogun, but was raised by the Hoshina clan, minor retainers of the once-powerful Takeda. Despite his unofficial status, Masayuki's talent could not be hidden. He was granted control of Aizu Domain, one of the most strategically important fiefs in northern Japan, with a nominal income of 230,000 koku. When his half-brother, the third shogun Tokugawa Iemitsu, died in 1651, Masayuki served as regent to the underage fourth shogun, Tokugawa Ietsuna. He wielded enormous influence, and his descendants were eventually permitted to use the prestigious Matsudaira surname and the Tokugawa family crest -- honors that recognized the bloodline everyone had always known about.

Masayuki was a devoted follower of Shinto, and in 1675, two years before his death, he established a shrine in Inawashiro to serve as both his final resting place and a subsidiary shrine to the kami of nearby Mount Bandai. His stone monument rises 7.3 meters tall, inscribed with his biography in the calligraphy of the scholar Yamazaki Ansai. The shrine's main hall, the honden, was originally built in the ornate Momoyama style reminiscent of the famed Nikko Tosho-gu. That building did not survive the Boshin War, the civil conflict that would eventually consume the entire Aizu domain, but the grave itself endures -- the lone patriarch standing apart from the successors who followed his spiritual example.

The remaining eight lords of Aizu rest together in a forest near the Higashiyama Onsen district of Aizuwakamatsu. From the second lord, Hoshina Masatsune, through the ninth and final lord, Matsudaira Katamori, their graves follow a distinctive pattern: octagonal crypts set on small earthen mounds, each preceded by a turtle-shaped pedestal and surrounded by votive stone lanterns called toro. Only Masatsune broke the Shinto tradition, receiving Buddhist rites. The rest followed Masayuki's precedent. The cemetery was renowned among feudal-era burial grounds for the sheer scale of its tombs and the beauty of its landscaped setting. Beyond the lords themselves, the grounds hold tombs of family members, descendants, and a hall of worship, creating a densely layered memorial spanning more than two centuries of the domain's existence.

The Aizu-Matsudaira family held private ownership of the cemetery grounds long after the feudal era ended. For over a century after the Meiji Restoration dissolved the domains, the family maintained the tombs as a personal responsibility. That changed in 2001, when ownership was transferred to the city of Aizuwakamatsu, which assumed responsibility for the site's environmental maintenance and historic preservation. The transfer ensured that the graves of nine lords -- men who governed a domain powerful enough to challenge an empire, yet devoted enough to honor a tradition that set them apart from every other clan in Japan -- would be cared for as public heritage rather than private burden.