After seeing the blood type named along with the height, weight, age, fighting style in video games fighters bio. I’ve discovered that Japanese people uses blood typing to describe people’s personality.
Blood type is indeed very important for the ‘can I say superstitious’ Japanese people.
Source: http://blog.gaijinpot.com/blood-type/
https://www.pdviz.com/you-are-what-you-bleed-japanese-bloodtyping
