Australia universally uses the No Hole Card rule for Blackjack and Pontoon. As such, it’s not possible to know if the dealer has a BJ until the end of the round which is an expensive penalty so the BB+1 and OBBO rules are used to compensate the player when the dealer turns over a BJ.

There are four main ways of dealing No Hole Card Blackjack…

OBO: If a player splits a pair and one of those hands bust then it stays on the table until the end of the round. This is the players original bet which is then lost if the dealer turns over BJ.

BB+1: If a player splits a pair and one of those hands bust then the cards and the bet are removed immediately. If the dealer turns over BJ at the end of the round then an additional bet is taken from the box. So the player loses his original bet which has already been removed plus one more (per box). If the player doubles his original bet and the dealer turns over BJ then only the original bet is lost.

OBBO: If a player splits a pair and one of those hands bust then the cards and the bet are removed immediately. If the dealer turns over BJ at the end of the round then an additional bet is taken from each hand. So the player loses his original bet which has already been removed plus one more (per hand). If the player doubles his original bet and the dealer turns over BJ then only the original bet is lost.

ENHC: European No Hole Card rule means the loss of all bets including splits and doubles if the dealer turns over BJ.

If no splitting has occurred then there is no difference between BB+1 and OBBO but for any game BB+1 is the better option. The Basic Strategy varies depending on which hole card rules the particular casino is using.