Flag of the Ishin Seito Shimpu, a nationalist political party in Japan
Vectorized version of flag from: https://ishin.biz/seironsya/%E7%B6%AD%E6%96%B0%E6%94%BF%E5%85%9A%E6%96%B0%E9%A2%A8-%E8%BA%8D%E9%80%B2%E3%81%AE%E9%9B%86%E3%81%84
Ishin Party Shimpu