Oasis Poker

Last update: June 15, 2007

Introduction

Oasis Poker is a variation of Caribbean Stud Poker. The rules of Oasis Poker are the same as Caribbean Stud, except the player is allowed to exchange cards before the raise/fold decision, for a price of course. The game can be found mostly in eastern Europe, northern Africa, and Internet casinos using Blue Chip Games software. Following are the complete rules.

Rules

1. The player makes an ante wager plus optional side bonus side bet.
2. Player and the dealer get five cards each. All cards are dealt face down, except one dealer card is exposed. The player may examine his own cards but sharing of information is not allowed.
3. The player has the option to switch one card of his choice for the next card in the deck. There is a fee to do this, equal to the ante wager. This fee is non-refundable.
4. The player may switch one of more cards. In this case, the fee for switching two cards is two times the ante, three cards for three times the ante, four cards for two times the ante, and five cards for one times the ante. If the player switches all five cards, then the player must raise.
5. The player may either fold or raise.
6. If player folds he forfeits his cards, ante bet, and side bet (if made).
7. If player raises then he must make a raise wager exactly equal to twice the ante.
8. The dealer will turn over his other four cards.
9. The dealer must have an ace/king or higher to qualify. In other words, the lowest qualifying hand would be ace,king,4,3,2.
10. If the dealer does not qualify then the player will win even money on his ante wager and the raise will push.
11. If the dealer qualifies and beats the player both ante and raise will lose.
12. If the dealer qualifies and loses to the player then the ante will pay even money and the raise according to the Raise Pay Table below. Other pay tables have been known to exist.
13. If the player and dealer tie then both the ante and raise will push.
14. The bonus bet win will be entirely based on the poker value of the player's original hand.

Strategy

I have never quantified a perfect card switching strategy. My program makes a perfect decision every time by analyzing all possible combinations of the replacement card and all four dealer cards. However, from running through some test hands I believe the following strategy is close to optimal.

The player should switch one card with any of the following:

1. Four to a straight flush and royal flush, even breaking up a pair
2. Four to a flush with no pair.
3. Four to an outside straight with no pair.

Do not switch with two pair or three of a kind.

If the casino allows switching two or more cards that option should never be taken.

Once the switch decision has been made the player can follow Caribbean Stud Poker strategy when deciding to raise or fold.

Odds

The following return table is based on the pay table above. Other pay tables are known to exist, which would change the odds.

The lower right cell shows a house edge of 1.04%.

After possibly switching and raising, the average final bet, including the switching fee, will be 2.183772 units. The element of risk is thus 0.475%. On average the player will switch 8.4% of the time.

At Internet casinos using Blue Chip Games software there are some rule changes. There the player may switch one to five cards, a full house pays 6 instead of 7, and there is a 0.3% rebate on all money bet. Before considering the rebate the house edge is 1.204%. The average final wager is 2.184 units. So the overall house edge is 1.204% - 0.3%×2.184 = 0.549%.

Side Bet

I indicate the odds of the side bet in my Caribbean Stud Poker section. Some casinos have been known to base the side bet on the hand after switching. This can be a very good rule for the player. However, if you see it, you're on your own.

Belgium Rules

In Belgium the player is allowed to switch cards, but if he does, he forfeits his option to fold. That version of the rules is addressed in my section on Belgium Variant of Oasis Poker.