Worth mentioning that the JCP is much more of a major mainstream party in Japan than communist parties are in most, or perhaps any, other western developed country.
Miyazaki himself also became somewhat more moderate in the early 90s while working on Nausicaa.
Eh, "major mainstream" is pushing it. They have 0.5% of the seats in the Diet, approximately similar representation in local government, and have never been part of a ruling coalition. Their membership is geriatric and their vote share slowly declining as well. AFAICT, the main reason they command any support is their staunch pacifism/anti-militarism, not economic policy.
Many post-Communist parties in Europe, like Germany's die Linke, have done much better. But unlike the JCP, they've also employed branding consultants and dropped the word "Communist", the hammers and sickles, etc.
They have about 270,000 members. Between both Diet houses they have 23 seats in total, which is 3.2%, not 0.5%. Their share of the popular vote was over 13% in 2014. By any measures that's massively more successful than, say, the Canadian Green Party.
