The Aizu domain code said it plainly: loyalty is not optional. The students of the 日新館 (Nisshinkan) school in 会津若松 (Aizuwakamatsu) learned it before almost anything else — that their lord, the 徳川 (Tokugawa) shogunate, was not merely a political master but a moral obligation. To abandon the Tokugawa in a crisis was not pragmatism. It was failure as a human being.

Matsudaira Katamori (松平容保, Matsudaira Katamori) had been adopted into the Aizu Matsudaira line, one of the most militantly loyal of all Tokugawa branch families. Born in 1836, he became the ninth lord of 会津 (Aizu) domain. When in 1862 he was appointed 京都守護職 (Kyoto Shugoshoku) — Military Commissioner of Kyoto, effectively chief of police for the Imperial capital in the most violent years of the 幕末 (Bakumatsu) — other advisers warned him the role was impossible. Kyoto was a cauldron of anti-shogunate violence, and the commissioner would be everyone's target. He accepted anyway. He was twenty-six years old.

For six years, Katamori held the Imperial capital. He was the organizing force behind the 新撰組 (Shinsengumi) — the elite loyalist police corps drawn originally from 浪人 (rōnin) and provincial warriors, wielding swords and extreme force to suppress the 尊王攘夷 (sonnō jōi) movement. The 新撰組 (Shinsengumi) operated under Katamori's authority throughout their existence; their patron and commanding lord was this young man from Aizu.

By 1868, the Tokugawa era was collapsing beyond rescue. The 戊辰戦争 (Boshin Sensō) — the civil war between Tokugawa loyalists and the Meiji imperial coalition — moved relentlessly north and east. 会津 (Aizu) became the final major holdout. Imperial forces besieged 鶴ヶ城 (Tsurugajō), Tsuruga Castle in 会津若松 (Aizuwakamatsu), from October 6, 1868. The siege lasted a month.

What happened during those weeks became the defining tragedy of the Meiji Restoration.

The 白虎隊 (Byakkotai), the White Tiger Unit, was composed of the teenage sons of Aizu samurai — boys of sixteen and seventeen organized into youth military units as the domain mobilized. One group of roughly twenty, separated from the main force during the fighting, retreated to nearby Mount Iimori. From the hilltop they looked down at the burning town below. Smoke rose from the castle district. The boys concluded the castle had fallen — that everything was lost. Following samurai tradition, they committed ritual suicide rather than survive in a defeated world. All twenty died. The castle had not fallen. It was still standing.

中野竹子 (Nakano Takeko) led what was called the 娘子隊 (Jōshitai), an unofficial corps of female warriors who took up 薙刀 (naginata) and fought the imperial advance without formal permission. On October 16, 1868, she was shot in the chest. As she lay dying, she asked her younger sister to cut off her head — so it could not be taken as a trophy by the enemy. Her sister complied, and the head was buried at a nearby temple.

Katamori surrendered on November 6, 1868. He was thirty-two years old. He and his son and senior retainers prostrated themselves before the imperial forces in unconditional surrender. His life was spared. He was placed under house arrest in Tokyo under the watch of the Tottori Domain for approximately four years.

The Meiji government, remarkably, did not simply destroy him. In 1880 they offered him a role: chief 神主 (kannushi), head Shinto priest, of 日光東照宮 (Nikkō Tōshōgū) — the sacred shrine built to enshrine Tokugawa Ieyasu (徳川家康, Tokugawa Ieyasu), the founder of the very dynasty Katamori had tried to preserve. He accepted. For thirteen years he burned incense and offered prayers at the grave of the man whose legacy he had spent his youth bleeding for.

It is not entirely clear whether this appointment was an act of mercy, a form of political containment, or a quiet joke by history. Perhaps all three. Katamori served faithfully until his death. He died on December 5, 1893, of pneumonia, at fifty-seven. He was buried by Shinto rites.

He had been one of the most powerful men in Japan. He had held the Imperial capital for six years. He had commanded the most feared police force of the age. And he spent his last thirteen years tending the tomb of the dynasty his loyalty had cost him everything to serve.