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

  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 end of this phase.
  2. Deal phase: The dealer draws 2 cards, 1 revealed and 1 hidden. Each player gets 2 cards.
  3. Play phase: Each player makes a move until he busts or stands, and then the next player moves.
  4. Finalize phase: After all players have moved, the dealer reveals the hole card. If not all players have busted, the dealer hits until the hand value is at least 17 (possibly hits on Ace and 6).
  5. End phase: Every player's 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.

Hand Values

Hands are ranked from best to worst in 21 categories:

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

Jack, Queen, and King are equivalent to 10. Ace has a value of 1 or 11.

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

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. 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), so bets must be an even integer. Paying 6 to 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.

Inverted (default: off)

Balance changes are negated.

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.

Decks (default: 1, min: 1, max: 9)

Number of decks to use. 9 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 Peek (default: on)

Dealer peeks and, after early surrender, ends the game immediately if there is a blackjack. Decreases house edge.

Typically on in American and off in European games.

Double

Doubling is allowed when the hand value is

Later options increase house edge.

Double After Split (default: on)

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

Surrender

Surrendering is allowed when

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

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: 3)

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

Hit Split Ace (default: on)

Allow hitting split aces. Decreases house edge. If hit with a 10, the blackjack is not a "natural" blackjack.