In Rurouni Kenshin: Meiji Kenkaku Romantan episode 5, they mention people fought to end the 4 social classes that existed in Japan, so all people would be equal. This is apparently a re-make of the 90's series; also there was a manga, OVAs, an animated movie, live action movies, etc. so I suppose anywhere it was mentioned. Also this might be what historically happened in Japan or not, since certain ideas are historically accurate, and others aren't or are loosely based. I suppose 2 of the social classes were farmer and samurai, but not sure which would be the others.
Which were the 4 social classes mentioned in Rurouni Kenshin Meiji Kenkaku Romantan episode 5?