In the series of articles on the science of poker, we will discuss a relatively new mathematical article published in 2015. The author of this article posits that preflop bluffing is a completely unprofitable action. To correctly understand this idea, we need to define the term bluffing.
The author, California Jack Cassidy, provides the following definition – it is a bet or raise strategy with the weakest hands. He indirectly clarifies this definition by including the worst 10% of hands (72o, 82o, etc.). Of course, such a strategy aims to force the opponent to fold better hands and take the pot preflop.
Two mathematical tools are created to analyze such situations – FlopShown and HOM (Hand Order Maintained). The first simulates a simplified version of Texas Hold ‘Em, where there are only two players with an infinite number of chips. The second analyzes how often the best hand preflop remains the best postflop.
During the mathematical analysis, it was observed that HOM is about 61% when transitioning from preflop to flop situations. This means that the best hand remains the strongest about 61% of the time. Bluffing with an extremely weak range becomes unprofitable because the strength of the hand does not change often enough when moving to the flop.
In poker practice, many regular players have already abandoned pure bluffing in preflop Heads-Up play. What is often used is what the author calls a semi-bluff – isolating with hands like 64s and similar. These hands have a better chance of connecting with the board than 72o or similar hands, but they are not inherently very strong. Such cards allow for more aggressive play postflop even without hitting a pair, as there will often be a possibility for a straight or flush draw.
One additional aspect to consider in this study is that players have an infinite number of chips. Every regular poker player knows that preflop play differs significantly when shallow. The opponent cannot respond as freely to large raises or ISO non all-in when the number of remaining mandatory bets is low. Of course, in any case, we will not go wrong by playing the weakest hands tightly and not often trying to represent monster hands with 72o.
