When you squint closely at the facts, not as much as you might think. Mostly, it is the difference between individual self-dealing and collective self-dealing.
As corporate policy, many Japanese companies re-hire their executive directors as “advisors (“sodanyaku” or “komon“) immediately after they retire from the board. The re-hiring occurs automatically, and the work expected from such “advisors” in their contracts (if any) is usually vague to the point of being non-existent.