How blackjack basic strategy works
Learn the right play for every hand, one decision at a time.
What basic strategy is
Basic strategy is the set of plays that minimizes the house edge in blackjack using only two pieces of information: your cards and the dealer's up-card. It was first worked out by hand in the 1950s and has since been confirmed by computer simulation of billions of hands. For every combination it names the single action, hit, stand, double or split, that loses the least or wins the most in the long run.
It is not a betting system and it does not beat the game. Played perfectly against typical Las Vegas Strip rules it brings the house edge down to roughly half a percent, compared with two percent or more for a player going on feel. Over a few hours at the table that difference is real money.
Why the dealer's up-card matters so much
The dealer has no choices: they must hit to 17 and stand there. That makes their final hand predictable from the up-card. Showing a 2 through 6 the dealer busts around 35 to 43 percent of the time, so you stand on weak totals and double aggressively to let them bust. Showing a 7 through Ace they usually finish with 17 or better, so you have to improve your own hand even at the risk of busting.
The rules this trainer assumes
Strategy charts change slightly with the rules. This trainer and its chart use the most common multi-deck game in US casinos:
- 4 to 8 decks
- Dealer stands on soft 17
- Double after split allowed
- Aces can be re-split
- No surrender
- Blackjack pays 3 to 2
Rule differences to know about
If the dealer hits soft 17 (H17) a few plays change: double 11 against an Ace, double soft 18 against 2, and double soft 19 against 6. Single- and double-deck games also differ in a handful of spots. This trainer teaches the multi-deck, stand-on-soft-17 chart, which is the most common game in US casinos.
How to use the trainer
Memorizing a chart by staring at it is slow. Repetition with immediate feedback is faster, which is what the trainer does:
- Press Deal to get two cards and the dealer's up-card.
- Choose Hit, Stand, Double or Split. On a keyboard: H, S, D or P.
- Read the verdict and the reason, then press Deal (or Enter) for the next hand.
- Pick a drill mode to focus on hard hands, soft hands, pairs, or your own mistakes.
What it does not do
This is a decision trainer, not a casino game. There is no bankroll, no betting, no dealer play-out and no card counting. Once you can play every hand correctly without thinking, you have mastered what basic strategy can offer.
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About this site
I built this trainer to learn basic strategy myself and to practice building web apps. It is a hobby project, free to use, and open to suggestions.