Classify of Indian Gamings

until today, I find a clear explaination on the classification of Indian games.
it's from http://500nations.com/Indian_Casinos.asp.

Class I Gaming
Defined as "traditional tribal gaming and social gaming" with minimal prizes.
There is no regulation outside of the tribal government.

Class II Gaming
Defined as gambling played exclusively against other players and not the house.
Examples are bingo, poker, and other “non-banked” card games.
These games are permitted on Indian land as long as they are legal elsewhere in the state.
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Class III Gaming
Defined as gambling played against the casino.
Includes slot machines, blackjack, craps, roulette, and "all forms of gaming that are not class I gaming or class II gaming."
Requires a compact with the state.