Help me findo

So, there's this yaoi manga I wanna find, here's the description:
It takes place in a school where they have this "game" that they play for, like, the whole year (I think). Anyway, it's basically a hierarchy based off cards (the king and queen on top, ect). Anyhow, so, every new year they play a game that decides your place, basically, the game masters put a bunch of cards all around the school and there's basically a giant Easter egg hunt for the cards. So, the first story is about a king who gets knocked all the way down to the bottom.
I think the word 'castle' was in it's title, somethin like 'Castle Heaven' or somethin.