What is Card counting?
Card counting is a blackjack technique that tracks the ratio of high to low cards remaining in the shoe so a player can raise bets when the remaining cards favour them.
High cards help the player: they make blackjacks more likely, which pay 3 to 2, and make the dealer bust more often. In the widely used Hi-Lo system, 2 to 6 count as plus 1, 7 to 9 as zero, and tens and aces as minus 1. A high positive count signals a favourable shoe.
Mathematician Edward Thorp showed in his 1962 book Beat the Dealer that blackjack could be beaten this way. Counting is legal in most jurisdictions because it uses only observation, but casinos may refuse play to suspected counters, limit their bets or reshuffle early. Using devices to count is illegal in many places.
Counting requires a large bankroll and discipline, and its edge is small, typically around 1% or less.
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