However, in the case of PS, the increase in house edge from the six-deck version 20/10 pay table (2.5723%) to the two-deck version 25/10 pay table (10.6796%) is enough to quash any such potential advantage. Reducing the number of decks normally increases the vulnerability of a bet to a card counting methodology. There are different pay tables for the two-deck and six-deck versions.

Sometimes the bet just doesn’t deserve it. I make no apologies for my lack of use of analytical power tools for this bet. Then I thought of a possibly stronger method. A few weeks ago I thought of a possible way to beat the bet. My approach will be considerably more simple-minded. The right way to estimate the maximum vulnerability of PS is to “integrate.” This gives the optimal earnings possible by using computer-perfect play. However, a simple thought experiment shows this wager must be vulnerable. There are no references to PS in Grojean’s “Beyond Counting,” and a Google search also comes up blank. This side bet has been around as long as the crows, but the question of vulnerability to advantage play has rarely been asked. This bet is also known by the name “Bet the Set,” though I have never understood that name, as a “set” usually refers to Three-of-a-Kind in poker. There is a premium payout if the pair is suited.

Pair Square (PS) is a simple-minded blackjack side bet that pays if the player’s first two cards are a pair.

Perfect pairs blackjack payout