The summer of 1949 was a season of fear in occupied Japan. The Shimoyama incident in July saw the president of Japan National Railway found dead on train tracks under circumstances never resolved. The Mitaka incident later that month involved a driverless train that killed six people, with suspicion falling on communist sympathizers. The Matsukawa derailment in August completed the trilogy. All three cases occurred against a backdrop of massive layoffs at Japan National Railway -- 100,000 workers were being dismissed under American occupation directives to restructure the economy. The government and occupation authorities pointed at organized labor and the Communist Party. Whether any of the three incidents were genuine sabotage, accidents, or provocations remains debated to this day. What is certain is that twenty people in Fukushima paid for the suspicion with years of their lives.

The first ruling came from the Fukushima District Court on December 6, 1950. All twenty defendants were found guilty, largely on the strength of confessions extracted during police interrogation. The sentences were savage: five defendants received death sentences, five were sentenced to life imprisonment, and the remaining ten received terms ranging from three and a half to fifteen years. On appeal at the Sendai High Court on December 22, 1955, the defendants recanted their confessions and proclaimed their innocence. Three were acquitted, but seventeen were again found guilty. Four received death sentences. Two received life imprisonment. The Japanese justice system had doubled down.

The turning point came from an unexpected quarter: literature. Author Hirotsu Kazuo wrote an essay in the literary journal Chuokoron that laid bare the contradictions in the prosecution's case. The essay ignited a movement. Some of Japan's most celebrated writers rallied to the defendants' cause: Yasunari Kawabata, who would win the Nobel Prize in Literature in 1968; Naoya Shiga, considered the father of the modern Japanese short story; Saneatsu Mushanokoji, the humanist novelist; Seicho Matsumoto, Japan's master of social detective fiction; and Eiji Yoshikawa, whose historical epics had made him a national treasure. The campaign was remarkable -- an entire generation of Japan's literary establishment declaring that justice had failed.

On August 10, 1959, the case reached the Supreme Court of Japan, which referred it back to the Sendai High Court for retrial. The decision was vindicated by what emerged during preparation: a document confirming the alibi of the accused had been deliberately hidden by the prosecution during previous trials. Forensic testing had also been suppressed -- testing that proved the spanner found near the derailment site was the wrong size and physically could not have been used to cause the accident. The prosecution had withheld evidence of innocence while sending people to death row. On August 8, 1961, at the Sendai High Court retrial, all defendants were found innocent. The prosecution protested, but on September 12, 1963, the Supreme Court upheld the verdict.

Legal proceedings dragged on until 1970, when the defendants were finally awarded compensation from the Japanese government for false arrest and imprisonment. Twenty-one years had passed since the derailment. The case was officially closed without ever determining the actual cause of the incident -- whether it was genuine sabotage by unknown parties, an accident, or something else entirely. The Matsukawa case became a landmark in Japanese legal history, a cautionary tale about forced confessions and prosecutorial misconduct that resonates in a country where criminal conviction rates still exceed 99 percent. In 2009, Fukushima University announced that archive files detailing the incident had been made public. A 1961 film directed by Satsuo Yamamoto, titled Matsukawa Jiken and starring Ken Utsui, told the story to a national audience -- its 45-million-yen production cost raised entirely by public donation.