>>1565639>>1571640>>1580149A "black company" is not necessarily minimum-wage. It's just a company with a really bad working environment. For instance, they might force you to do unpaid overtime, berate you if you don't perform, not follow the labour laws properly, or be exploiting their workers in other ways. It has nothing to do with how big or small the salary is.
Also, anyone can afford to live in Tokyo but you'll live in a shoebox and eat nothing but bean sprouts if you insist on living centrally despite only making minimum wage. Most people who work in Tokyo, like myself, live in the outskirts. Like Nerima, Yokohama, Funabashi, etc. Commuting from either of those places to central Tokyo only takes about 40 mins by train.