Please read An article on BBC UK written on April 28, 2010 here. I feel it is in some degree exaggerated, as personally I have never been asked about blood group in job interviews, but it is true that there are many people who cares typical character by blood group and chemistry between blood groups.
If you search in Amazon.co.jp, using the query 血液型, that means blood group, you find as much as 3,816 Japanese books as of today. (For your reference, If you search in Amazon.com using "blood type", you find 1,861 books.)
They say;
The blood group A;
- sense of responsibility
- prudent
- serious
- perfectionist
- picky
The blood group B;
- optimistic
- easygoing
- social
- full of idea
- lack the common sense
The blood group O;
- boss person
- realistic
- generous-hearted
- pervious
- moody
The blood group AB
- analytic
- handy
- dual nature
- fair-mindedness
- calculating
What do you think?