It's probably not, man. I live in Korea but know many people who who lived in Japan before. The two countries are similar in this respect - you will always be a foreigner.
Doesn't matter if you live there for 10 years, have a Japanese wife, speak fluent Japanese, you'll never be truly accepted.
It's one of the most homogenous societies on the planet. Casual racism (more like xenophobia I guess) is very high and, unlike in the west where xenophobia gets called out, in East Asia some drunk old guy could scream at you on the subway to go back home and no one will say a thing against them.
I like living in Korea, it has many great things going for it. I have a Korean girlfriend, I'm learning Korean, I became interested in the culture, history and love the food. But I still experience indirect or direct xenophobia constantly. I'd like to live in Japan too and maybe will. But I could never belong to either country.