Single Deck Blackjack

Several studios deal a one-deck game here, and their rules screens do not agree. Read the payout first: the same small deck is a bargain at 3:2 and one of the dearest tables anywhere in the free library at 6:5.

In a single deck, every card on the table noticeably changes what is left. A player holding an ace faces a remaining deck in which ten-valued cards make up a larger share than they would after the same ace left a six-deck shoe, so the blackjacks that pay 3:2 arrive slightly more often. Doubles gain in the same way: a player doubling 9, 10 or 11 holds small cards that are no longer in the deck, and what remains leans toward the tens that complete the double.

When the dealer stands on soft 17, with a double after a split allowed, those effects turn the standard game around. Against the same rules from six decks, one deck cuts 0.55 points from the house edge and leaves a player using basic strategy ahead by 0.14%.

The key number: One deck instead of six is worth 0.55 points to the player, more than the whole house edge of the standard six-deck game.

Every figure on this page assumes a freshly shuffled deck for each hand, as an online table deals, so the gain comes from the cards of a single deal alone. Following the cards from one round to the next is a separate matter, explained on the card counting page.

With a soft-17 stand and doubling after splits, 14 cells of the shoe chart change at one deck, nearly all toward more doubles and more splits. Letters as on the strategy charts: H hit, S stand, D double (otherwise hit), Ds double (otherwise stand), P split. When the dealer hits soft 17 instead, the list is the same except soft 18 against an ace, which stays a hit; the basic strategy guide carries both one-deck charts.

All rows share the rest: doubling on any two cards, up to four split hands, aces split once, no surrender, and a dealer who checks for blackjack. In the first row the small advantage belongs to the player rather than the house, and every edge is for a player using the chart that fits that row.

Single-deck tables have traditionally paired the one deck with two rules that favor the house: the dealer hits soft 17, and a double after a split is not allowed. The combination is known as the downtown rule set.

With a 3:2 payout it still costs little. Basic strategy then faces a house edge of 0.19%, still under the 0.41% of the standard six-deck game, so the deck still gives back more than the two rules take. Without doubling after a split, the small pairs are split less often against weak upcards, which alters a few cells of the pair chart.

A 6:5 payout shortchanges every blackjack the player is dealt. Naturals are a small share of hands, but each one pays less, and in the standard game the lower payout costs the player 1.36 points, far more than one deck gives back. How 6:5 and 1:1 compare with 3:2 at every deck count, in money per 100 rounds, is the subject of the blackjack payouts page.

The comparison that matters is with an ordinary shoe. A downtown single deck paying 6:5 carries a house edge of 1.58% with basic strategy, while a six-deck shoe with the dealer hitting soft 17 and a 3:2 payout carries 0.62%. The single deck looks like the better table and is the more expensive one by a wide margin.

The rule: Check the blackjack payout before the deck count: a 6:5 single deck returns less than a 3:2 game dealt from any shoe.

Arrow's Edge, Genesis Gaming and Platipus each offer a game called Single Deck Blackjack, and Urgent Games deals one deck in Blackjack Premium - Single Deck. Their payout and soft 17 lines are set by each provider, and the rule-set table on this page shows what each combination is worth.