Blackjack: the rules and the arithmetic underneath

The game uses a standard 52-card deck, commonly several of them shuffled together. The dealer draws to a fixed rule — standing on 17 in the classic form described by Bicycle's official rules — which means the dealer has no decisions at all. A natural blackjack — ace plus a ten-value card in your first two — traditionally pays 3:2; insurance, offered when the dealer shows an ace, pays 2:1 and remains a bad bet for a basic-strategy player in the long run.

Basic strategy is the precomputed table of the correct decision for every hand against every dealer upcard. Cornell's mathematics outreach page puts the game's edge for a basic-strategy player at about 0.16% under favourable classic rules — a fraction of what any intuitive player concedes. The table is not memory-heroics: most of it compresses into a dozen patterns, and printing it costs nothing. The single most expensive habit at the table is improvising hands the chart already solved.

Two rule changes to watch before sitting down: a table paying less than 3:2 on a natural raises the house edge sharply — treat any reduced blackjack payout as a different, worse game; and the number of decks, the dealer's soft-17 rule, and restrictions on doubling all move the edge in ways the felt will not advertise. The info panel of a live online table lists these rules; read it the way you read a slot's RTP line.