The Japanese Communist Party (JCP) turns one hundred this year, which is inevitably sparking much discussion about its history. The meeting that launched the first organized force for Japanese communism took place a century ago today on July 15, 1922.

Amid the welter of backslapping about its resilience and analysis of its shifts in policy and character, it is perhaps easy to forget that, for a time, the party seemed to many on the Left in Japan like a has-been — or even an archenemy. During the 1960s, the myriad elements of the Japanese New Left appeared to be on the verge of seizing the ascendancy from the JCP, which they regarded as a repellent and counterrevolutionary force.

In a wide-ranging 1994 survey of former student activists who took part in the campus protests of the Long ’60s, a man who attended Toyo University and participated in the social movements of the time listed the JCP leaders as the politicians he now “most hated.” Notably, he ranked them ahead of the Liberal Democratic Party (LDP), the conservative party that has ruled Japan continuously since 1955 with the exception of two brief periods. Where did such vehemence come from, and why has it lingered for so long?