What Basic Strategy Actually Is
Basic strategy is the mathematically correct decision for every possible blackjack situation — every combination of player hand and dealer up card. It was developed in the 1950s by a group of mathematicians who ran the first computer simulations of blackjack odds. The strategy they produced has been refined over decades and is now exact: for every hand you can be dealt and every card the dealer shows, there is one decision that produces the best possible expected outcome over time.
Basic strategy is not a guarantee of winning any given hand. It is the set of decisions that minimizes the house edge across millions of hands. Played exactly, it reduces the casino's advantage to approximately 0.5% under standard conditions. That is the lowest house edge available to any casino player who is not counting cards.
Why the Strategy Chart Is Always Right
Every decision in basic strategy is derived from probability. When you hold a 16 against a dealer 10, the strategy says hit. This feels wrong — you are likely to bust. But the mathematics show that hitting a 16 against a 10 loses less money over time than standing, because a dealer showing 10 completes a strong hand often enough that your 16 would lose to it regardless. The strategy chooses the option that loses less — not the option that feels safer.
The Core Principle
Basic strategy never asks which decision wins. It asks which decision loses less money over time. Sometimes the correct play still loses — frequently, in fact. But the correct play loses less than any alternative would over thousands of repetitions. This is what expected value means in practice.
The Key Strategy Decisions Explained
When to Stand
Stand on hard 17 and above — always. The probability of busting when hitting 17 is too high to justify regardless of the dealer's card. Stand on hard 13 through 16 when the dealer shows 2 through 6. The dealer is in bust territory with a low up card — let them potentially bust rather than risk your own hand. Stand on soft 18 when the dealer shows 2, 7 or 8.
When to Hit
Hit on hard 11 or less — you cannot bust with one card. Hit on hard 12 through 16 when the dealer shows 7 through Ace. The dealer has a strong hand and you need to improve. Hit on soft 17 or less — always. A soft 17 is a weak hand that benefits from drawing.
When to Double Down
Double on hard 11 against any dealer card except an Ace. Double on hard 10 against dealer 2 through 9. Double on hard 9 against dealer 3 through 6. Doubling puts more money on the table when you have an advantage — the opportunity should never be passed up when the strategy calls for it. Failing to double when correct is one of the most expensive casual player mistakes.
When to Split
Always split Aces and eights. Aces split into two potential 21s. Eights split because 16 is the worst hand in blackjack and splitting gives two chances at a better result. Never split tens or fives — a 20 is too good to break up, and a 10 is better used as a double-down hand. Split twos, threes and sevens against dealer 2 through 7. Split sixes against dealer 2 through 6. Split nines against dealer 2 through 6 and 8 through 9.
When to Surrender
Where late surrender is available, surrender hard 16 against dealer 9, 10 or Ace. Surrender hard 15 against dealer 10. Surrendering returns half the bet — the correct choice when the probability of losing is high enough that half the bet is worth recovering. Most casual players never surrender because it feels like giving up. Mathematically it is the correct play in the situations listed.
Rule Variations and Their Cost
Basic strategy assumes a specific set of rules. Every rule variation from the standard game changes the house edge. Knowing which rules are good for players and which benefit the casino is essential before sitting down.
| Rule Variation | Effect on House Edge | Good or Bad? |
|---|---|---|
Blackjack pays 3:2 | Standard — baseline | Good — seek this out |
Blackjack pays 6:5 Common on single-deck games | +1.39% house edge | Bad — avoid this table |
Dealer stands on soft 17 | Standard — baseline | Good |
Dealer hits soft 17 | +0.22% house edge | Slightly worse |
Double after split allowed | −0.14% house edge | Good — look for this |
Late surrender available | −0.08% house edge | Good — use it correctly |
Each extra deck in shoe | +~0.02% per deck | Slightly worse |
The 6:5 Blackjack Trap
Many casinos — especially those offering single-deck blackjack — pay 6 to 5 on a natural blackjack instead of the traditional 3 to 2. On a $10 bet, 3:2 pays $15. 6:5 pays $12. The difference is $3 per blackjack. Since blackjack occurs approximately once every 21 hands, this costs the player roughly $3 per 21 hands or about 14 cents per hand at $10 bets. This adds 1.39% to the house edge — turning a 0.5% house edge game into a 1.89% game before any other adjustments. It erases most of the benefit of playing correctly.
Always check the felt for payout rules before sitting down. If the felt says Blackjack Pays 6:5, find another table. The game is not worth playing at those terms regardless of how appealing the single-deck format looks.
Insurance — Why It Is Never Correct
When the dealer shows an Ace, insurance is offered before the dealer checks for blackjack. The bet pays 2 to 1 if the dealer has a ten-value down card. To break even on insurance, approximately 33.3% of unseen cards would need to be ten-value. In reality, 30.8% of cards in a standard deck are ten-value. The house edge on insurance is 7.69%. Basic strategy says never take insurance — including never taking even money when you hold a blackjack. The mathematics do not change based on your hand strength.
The Bottom Line
Basic strategy reduces the house edge to approximately 0.5% — making blackjack one of the best bets in any casino. The strategy is not difficult to learn. A strategy card available at most casino gift shops is legal to use at the table in virtually every casino. The most expensive thing a blackjack player can do is play without it. The second most expensive is sitting at a table paying 6 to 5 on blackjack.
Memorize the key decisions — stand on 17 and above, double on 10 and 11, always split Aces and eights, never take insurance — and you are already playing better than the majority of the people at your table.