Male bras. (No, I don't understand either).
Blood Groups: the Japanese equivalent of horoscopes or Myers-Briggs tests apparently, and hugely popular as an explanation for all personal issues. Just in case you were wondering, here's some examples of the incisiveness of the personality insights you can gain from looking at things this way.
- Type A Reserved and prone to worry, sensitive perfectionists such as Britney Spears and Adolf Hitler.
- Type O Decisive, self-confident, curious, and ideal for sport, including Elvis Presley and the Queen.
- Type B Cheerful caring, flamboyant free-thinkers such as Jack Nicholson.
- Type AB High-maintenance, distant, suited to arts, such as Mao Zedong.