The Japanese Communist Party is riding high.

With the public increasingly dismayed by the thin results of Abenomics and wary of Prime Minister Shinzo Abe's aggressive stance on defense, the party has tapped into anti-Abe sentiment over the past few years. It more than doubled its seats in the 2014 Lower House election.

In the run-up to the Upper House election this summer, the JCP is playing a pivotal role in an electoral tie-up with opposition parties that agree on one thing: Abe must go.