JAPANESE voters went to the polls last weekend in local elections that set few pulses racing: turnout was the lowest on record and the Liberal Democratic Party (LDP), the dominant partner in Japan’s ruling coalition, cruised to victory predictably, winning over half the nation’s prefectural assembly seats. But another political success did surprise: the Japanese Communist Party (JCP) emerged as the country’s largest opposition at the local level.

The JCP took 136 seats, knocking the centrist Democratic Party of Japan (DPJ)—which ran the country just five years ago—into fourth place behind Komeito, the LDP’s coalition partner. The result followed notable gains made by the JCP in a general election in December, when they took more than 6m votes, bringing up their share of parliamentary seats from 8 to 21: the party’s best showing in nearly two decades.

Though the Communist party has never looked remotely close to taking power (its best electoral performance yet was in 1979, when it won 39 seats out of a total of 511), it remains a force in Japanese politics. The party has over 300,000 members, including 10,000 it says it recruited in 2014 (the LDP claims around 790,000). It also publishes a newspaper, Akahata ("Red Flag"), which has a daily circulation of about 1.2m.

The JCP’s platform has changed little in decades: its main aims are to overturn capitalism; to scrap Japan’s armed forces eventually; and to end the country’s 60-year-old military alliance with America. The party’s renewed popularity is mostly a measure of the public’s frustration with mainstream politics, says Jeff Kingston of Temple University in Tokyo. It has capitalised on the electorate’s concerns about the right-wing government of Shinzo Abe, Japan’s prime minister, by rejecting his attempts to restart nuclear plants, cut corporate taxes and weaken restrictions on Japan’s military forces—all of which have gathered pace this year under Mr Abe’s stewardship. The JCP’s recent popularity boost is also a result of its stand against an unpopular hike in the consumption tax last year.

The party’s increased representation since December has allowed it to propose new laws, for the first time in years. Though its website pledges to end Japan’s “extraordinary subordinate relationship” to America, in practice the JCP focuses on narrower struggles. The bills it has submitted this year attempt to limit corporate funding for political parties and to place tighter controls on companies that overwork young employees. One a perennial gripe of voters and the other a recent grievance, they are both bound to be popular with the public.