Rules for Blackjack

Gameplay

Blackjack is a popular comparing card game.

The decks of cards are shuffled and placed into the shoe, from where cards are drawn. If the shoe is empty, it is refilled completely.

Rounds

Each round consists of these phases:

  1. Bet Phase: Each player simultaneously places a bet, up to max(the player's balance + 200, 100). Bet amounts are not revealed until the next phase.
  2. Deal Phase: The dealer gets 2 cards, 1 face-down and 1 face-up. Each player gets 2 cards. The cards are dealt in this order:
    1. Players get one card each.
    2. The dealer gets the face-down hole card (or face-up revealed card if there is no hole card).
    3. Players get their second cards.
    4. The dealer gets the face-up revealed card (if there is a hole card).
  3. Pre-Play Phase: If the dealer reveals an Ace, each player can purchase insurance of (up to) half of the bet. If surrendering is possible, each player can surrender.
    • Before (late surrender) or after (early surrender), the dealer peeks at the hole card (if applicable).
    • When the dealer peeks, the game ends immediately if there is a blackjack.
  4. Play Phase: Each player makes a move until he busts or stands, and then the next player moves. All players move at the same time if Speed is enabled.
  5. Post-Play Phase: If applicable, players get an offer to buy insurance after the Play Phase instead of the Deal Phase.
  6. End Phase: The dealer reveals the face-down hole card. Unless all players have blackjack, busted, or surrendered, the dealer hits until the hand value is at least 17 (possibly hits on soft 17). Every hand is compared against the dealer's, and payouts are processed.

Payout

The better hand wins the bet amount.

If the player has a natural blackjack while the dealer does not, a bonus is paid on top.

If the player's hand busts (exceeds 21), the dealer wins, even if the dealer also busts.

If the hands are otherwise equal, it is a "push" and neither side wins.

Card Ranks

The cards (4 each per deck) are in this order from lowest to highest:

Ace (as 1) < 2 < 3 < 4 < 5 < 6 < 7 < 8 < 9 < 10 = Jack = Queen = King < Ace (as 11)

Jack, Queen, and King are equivalent to 10, so the interface combines them. Ace has a value of 1 or 11.

Hand Values

Hands are ranked from best to worst in 21 categories:

  1. Natural blackjack (best): non-split Ace and 10
  2. 21 to 3 (19 categories): ordered by hand value descending
  3. Bust (worst): hand value is 22 or higher

The hand value is intuitively the best possible sum of card values.

Formally, the hand value is the hard hand value if the soft hand value exceeds 21; otherwise, it is the soft hand value. The hard hand value is the sum of card values, treating Ace as 1. The soft hand value is the hard hand value, plus 10 if there is at least one ace.

Moves

If the dealer shows Ace, during the Pre-Play (or Post-Play, depending on the game mode) phase, each player can bet (up to) half of the bet as insurance, which pays 2:1 if dealer has a blackjack.

If surrendering is allowed, it is possible to do it during the Pre-Play phase. The game mode can also allow surrendering during the Play phase.

During the Play Phase, players can make these moves: (unless hand value is 21 or more)

Time Control

Intermissions last up to 30 seconds, ending early if all players are ready.

Each turn lasts up to 20 seconds by default, with automatic Stand and 0 insurance. Unused turn time cannot be carried to future turns. There is only a turn timer, not a game timer.

Options

Blackjack pays 3 to 2 (50% bonus), and maximum insurance is half of the bet amount, so bets must be an even integer. Supporting both 3:2 and 6:5 would require bets to be multiples of 10. This option might be added in the future.

Turn Time / s (default: 20, min: 5, max: 60)

An automatic move will be made after the turn timer expires.

Speed (default: on)

All players move in the same turn. Cards drawn are given to the first player to move. The turn timer is reset whenever any player makes a move.

Inverted (default: off)

Balance changes are negated.

Decks (default: 1, min: 0, max: 251)

Number of decks to use. 0 is treated as ∞ decks. Increases house edge.

Dealer Hits on Soft 17 (default: on)

Dealer hits on soft 17 instead of standing. Increases house edge.

Dealer Hole Card and Peek

Surrendering is allowed when

Typically Hole Card Peek Early in American games and No Hole Card in European games.

If Simple is enabled or surrendering is disabled, Hole Card Peek Late will be set to Hole Card Peek Early.

Later options decrease house edge.

Simple (default: off)

Play with the simpler rules of 21, without the new rules in Blackjack. Just Hit or Stand, without worrying about splitting, doubling, surrendering, or insurance.

Double

Doubling is allowed when the hard hand value is

Later options increase house edge.

Double After Split (default: on)

After splitting, allow doubling each hand separately. Decreases house edge.

Surrender After Split (default: off)

After splitting, allow surrendering each hand separately. Decreases house edge.

Surrender After Hit (default: off)

Allow surrendering a hand of more than two cards. Decreases house edge.

Surrender

Surrendering is allowed

Later options decrease house edge.

Split Non-Ace (default: 3, min: 0, max: 254)

Pairs of 2 to 10 can be split N times to make N+1 hands. Decreases house edge.

Split Ace (default: 1, min: 0, max: 254)

Pairs of aces can be split N times to make N+1 hands. 10 with a split ace is not a natural blackjack. Decreases house edge.

Hit Split Ace (default: on)

Allow hitting or doubling split aces. Decreases house edge.

Partial Insurance (default: on)

Allow insuring up to (rather than exactly) half of initial bet value.

Late Insurance Offer (default: off)

Move the Insurance Phase to after all players have moved. The offer is based on the total number of unsurrendered hands.

This option will be disabled if Hole Card Peek is on.