There are generally two kind of people in management or leadership: (1) the cool and quiet guy (2) the energetic and charismatic guy. I shall refer the first as Type A and latter as Type B.

Asian (particularly Japanese) believes there is a colloration between their blood type and their character. This is not to say all Type A managers have blood type A etc, but an interesting belief nonetheless.

Over the years, I observed that Type A managers likes to have Type B as their reports. Likewise, Type B managers like to have Type A reports. If both of them are Type A, then the team is too passive. If both of them are Type B, then there would too much conflict.

It is common to find alternating Type A and Type B as you tranverse the management hierarchy: Type A CEO will have Type B CXI who will have Type A VPs who will have Type B Directors etc.