Examining the billionaires' blood type (top to No. 10) of Forbes' "the world's billionaires 2018", they are all Type O, both in the world and Japan.
As expected, O is good at making money.
However, this only shows a "trend" since the blood type of the majority is unknown.
<World>
No. 2 Bill Gates / $90 billion (Microsoft)
No. 3 Warren Buffett / $84 billion (Berkshire Hathaway)
No. 4 Mark Zuckerberg / $71 billion (Facebook)
<Japan>
No. 1 Masayoshi Son / $21.9 billion (Softbank)
No. 2 Tadashi Yanai / $19.3 billion (Fast Retailing)
No. 7 Hiroshi Mikitani / $5.4 billion dollars (Rakuten)
No. 9 Akio Nitori / $4.8 billion (Nitori)