How to count cards in blackjack

Blackjack is one of the only casino games where the past changes the future. As cards leave the shoe, the composition of what remains shifts, and the player's edge shifts with it. When the remaining shoe is rich in high cards (10s and aces), three things help you: blackjacks become more likely and they pay 3 to 2, your doubles and splits become more profitable, and the dealer, who must hit stiff hands, busts more often. When the shoe is rich in low cards, the reverse is true and the house edge grows.

Counting is simply keeping score of that shift. You do not track which cards remain. You track whether the cards that left were mostly high or mostly low, which tells you what is left. When the count says the shoe favors you, you bet more. When it does not, you bet the minimum or sit out. That is the entire game.

The edge is small, roughly half a percent to one and a half percent for a skilled counter, and it arrives wrapped in enormous variance. Counting does not make you win every session. It makes you a small favorite over thousands of hands, which is why bankroll sizing is half the skill.

Hi-Lo assigns every card one of three values. That is the whole system to memorize:

Step 1: the running count. Start at zero when the shoe is shuffled. As each card appears, add its value. A 5 (+1), then a king (−1), then a 9 (0): the count goes +1, back to 0, stays 0. Cancel pairs as you see them instead of adding one at a time: a low card and a high card together are always 0.

Step 2: estimate decks remaining. Glance at the discard tray and judge how many decks have been dealt, to the nearest half deck. This is a visual skill; practice by stacking known numbers of decks next to a discard tray until your eye calibrates.

Step 3: convert to the true count. Divide the running count by the decks remaining. Running count +6 with 3 decks left is a true count of +2. The true count is the number that drives every decision.

Step 4: bet with the count. Each true count point is worth roughly 0.5% of edge. With perfect basic strategy costing about 0.5% off the top, the game turns in your favor around a true count of +1 to +2. A common illustrative ramp: bet the minimum at +1 or below, 2 units at +2, 4 at +3, and your max at +4 and up. Real spreads are tuned to the bankroll and to how much attention the player wants to avoid.

Most of a counter's profit comes from bet sizing, but a few plays also change with the count. Standing on 16 vs 10 becomes correct when the true count reaches 0, and taking insurance becomes correct at +3. The Illustrious 18 lists the count plays worth learning, in order of value. Learn them after the count itself is automatic.

Week 1: one deck, no clock. Flip through a single deck one card at a time, keeping the count. A full deck always ends at zero, which is your answer key. Then flip two at a time, canceling pairs.

Week 2: add speed. Use the count drill. Start with 10 cards on slow, graduate to full-deck rounds on fast. Target: a full deck in under 30 seconds with zero errors.

Week 3: true count conversion. Deal a running count, estimate decks remaining from a discard pile, divide. Repeat until the division is boring.

Week 4: casino conditions. Count with the TV on, while conversing, while someone deals fast and asks you questions. Then add basic strategy decisions on top: deal yourself hands, play them correctly, and never lose the count. The trainer handles the strategy half.