According to wikipedia, that guy committed sepuku?
I was pretty sure I was thinking of some european leader, too. Perhaps not a king, though, but someone of great importance.
Nobunaga Oda was the guy who at his prime (he essentially controlled kyoto - capital, imperial courts, etc, and most of central japan.. no doubt on his way to become shogun) ticked his vassal off so badly that the vassal rebelled and whacked him (and his retinue) where he was resting.
whether he chopped himself or not is not too relevant.. higher up people tend to chop themselves before someone else chop them back then too.
