Five years is a long time to bleed together.

The 新選組 (Shinsengumi) had been formed in 1863 as a shogunate police force in Kyoto — a squad of low-born swordsmen given legal authority to cut down anyone who threatened order. They had used that authority extensively. The 池田屋 (Ikedaya) raid of 1864, where they fought through a burning inn to break up an imperial loyalist conspiracy, became their founding myth. The street battles of the 幕末 (Bakumatsu) filled their ranks and then emptied them. By 1868, the original unit had been reorganized and renamed the 甲陽鎮撫隊 (Kōyō Chinbutai, Pacification Corps) and assigned to march on 甲斐 (Kai) Province — the same mountains where the 武田 (Takeda) had made their last stand almost three centuries earlier.

The 甲陽鎮撫隊 (Kōyō Chinbutai) was defeated at the Battle of 甲州勝沼 (Kōshū-Katsunuma) in late March 1868 and forced to retreat to Edo. The shogunate's armies were crumbling across every front. Imperial forces were closing on the city.

It was in the aftermath of this defeat — according to accounts attributed to 永倉新八 (Nagakura Shinpachi) — that 近藤勇 (Kondō Isami) made his request. He asked the surviving men to formally become his 家来 (kerai) — his personal retainers, bound to him as lord.

The word kerai carried weight that a Western soldier might not immediately feel. It was not simply loyalty to a commander. It was the formal subordination of one person to another within a feudal hierarchy — the acknowledgment that you were beneath, and he was above. In a unit whose founding mythology was built on 義 (gi) — righteousness, duty freely chosen — the demand felt like a category error. Or worse: like Kondo using the moment of the shogunate's collapse to elevate himself at the expense of the men who had built his reputation.

Nagakura Shinpachi, who had served as captain of the Second Unit, refused. 原田左之助 (Harada Sanosuke), captain of the Tenth Unit, refused with him. Both had joined the Shinsengumi as independent swordsmen — free men choosing a cause, not subordinates accepting a master. They had, by some accounts, helped make Kondo famous. They would not become his retainers in defeat when they had not been his retainers in victory.

The two men took a group of followers and formed the 誠平隊 (Seiheitai), with a former Tokugawa retainer named Haga Gido as its nominal commander. They did not desert. They marched north toward 会津 (Aizu) and the fighting that remained — choosing a different chain of command but the same cause. Their departure was not betrayal; in their own understanding, it was the only act consistent with 義 (gi).

The Shinsengumi as a coherent unit ceased to exist.

土方歳三 (Hijikata Toshizō), the vice-commander, continued fighting — through the northern campaigns, through the fall of Aizu, all the way to 北海道 (Hokkaidō), where he died at the Battle of 箱館 (Hakodate) in May 1869. He is remembered as the last Shinsengumi captain to fall.

Kondo Isami survived six more weeks. He was captured by imperial forces at 流山 (Nagareyama) on April 26, 1868, and executed by beheading on May 17 at 板橋 (Itabashi). His head was salted and sent to Kyoto, where it was displayed on a pike at 三条大橋 (Sanjō Ōhashi) bridge — the same bridge where the Shinsengumi had once posted notices threatening execution to any ronin who disturbed the peace. History has a dark sense of geometry.

Harada Sanosuke, who had refused to kneel to Kondo, returned to Edo after leaving the Seiheitai to be with his wife and son. He joined the 彰義隊 (Shōgitai), a pro-Tokugawa militia, and fought at the Battle of 上野 (Ueno) on July 4, 1868. He was shot. He died of his wounds two days later, on July 6. His son, whom he had named Shigeru — taking a character from the name of 将軍徳川家茂 (Shōgun Tokugawa Iemochi), a private act of loyalty to the dying regime — was left fatherless in the ruins of the Bakumatsu.

Nagakura Shinpachi, the last surviving senior captain of the Shinsengumi, made it to the other side.

He moved to Hokkaido, found work as a kendo instructor for prison guards, later opened a dojo in Tokyo, and — in 1911, more than forty years after the events — gave oral histories of the Shinsengumi to newspaper reporters. The accounts he dictated became part of the foundation of the Shinsengumi's mythology. He also wrote a memoir and lent it to an acquaintance who never returned it. The firsthand written account of the Shinsengumi by its longest-surviving senior captain was lost because of a careless loan.

Nagakura died in 1915 at age 77. The most lethal swordsman of the Bakumatsu died in bed.

The fracture of the Shinsengumi over a question of pride is the human face of the shogunate's collapse. Grand events — neutrality declarations, armies marching on Edo — were political and military abstractions. This was personal: men who had chosen each other across five years of shared danger, discovering that their brotherhood had a limit. The fall of the samurai age was not only fought in battles. It was lived in moments like this one — in a disagreement over a word, in a refusal to kneel, in the silence after two captains walked out the door.