Card Counting

Detailed Explanation

Card counting is a legal advantage play technique in blackjack that tracks the ratio of high cards (10-value cards and Aces) to low cards (2–6) remaining in the unplayed portion of the shoe. When the remaining deck is rich in high cards, the player has a statistical advantage; the counter increases their bet. When the deck favours low cards, the house has a greater edge; the counter minimises their bet.

The most common system is the Hi-Lo count: assign +1 to cards 2–6, 0 to 7–9, and -1 to 10-value cards and Aces. The running count divided by the number of remaining decks (in half-deck increments) yields the true count. A true count of +2 typically yields a player edge of approximately 0.5%; at +4, the edge may reach 1–2%.

Card counting is not illegal, but casinos reserve the right to refuse service to any patron. Known counters are typically backed off and may be banned from a property. The practice requires extensive practice — mastering Hi-Lo to casino-floor proficiency typically requires 200+ hours of dedicated training.