blackjack_rules.html

---
title: Rules for Blackjack
date: "2020-10-03 15:24:00 -0600"
mdate: 2021-02-21 11:13:41 -0700
---
{% include game-tab.html game='blackjack' %}

<h1>Gameplay</h1>
<p>Blackjack is a popular comparing card game.</p>
<p>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.</p>

<h2>Rounds</h2>
Each round,
<ol>
  <li>Each player places a bet, up to max(the player's balance + 200, 100).
  <li>The dealer draws 2 cards, 1 revealed and 1 hidden. Each player gets 2 cards.
  <li>Each player makes a move until he busts or stands, and then the next player moves.
  <li>After all players have moved, the dealer reveals the hole card, and then hits until the hand value is at least 17 (possibly hits on Ace and 6).
  <li>Every player's hand is compared against the dealer's, and payouts are processed.
</ol>

<h3>Payout</h3>
<p>The better hand wins the bet amount.</p>
<p>If the player has a natural blackjack while the dealer does not, a bonus is paid on top.</p>
<p>If the player's hand busts (exceeds 21), the dealer wins.</p>
<p>If the hands are otherwise equal, it is a "push" and neither side wins.</p>

<h2>Hand Values</h2>
<p>Hands are ranked from best to worst in 21 categories:</p>
<ol>
  <li>Natural blackjack (best): Ace and 10, except for 10 after hitting split Ace
  <li>21 to 3 (19 categories): ordered by hand value descending
  <li>Bust (worst): hand value is 22 or higher
</ol>

<p>Jack, Queen, and King are equivalent to 10. Ace has a value of 1 or 11.</p>
<p>The hand value is intuitively the best possible sum of card values.</p>

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

<h2>Moves</h2>
<ul>
  <li>Hit: get 1 card (turn ends if value exceeds 21)
  <li>Stand: end turn
  <li>Double: if hand has 2 cards, double bet amount, get 1 card and stand
  <li>Split: with a hand of two equal-value cards, move one to a new hand, add a bet to the new hand equal to the original bet, and draw one card for both hands
  <li>Surrender: if hand has 2 cards, forfeit half of bet
  <li>Insurance: if dealer shows Ace, bet up to half of bet, which pays 2:1 if dealer has a blackjack.
</ul>

<h1>Time Control</h1>
<p>Intermissions last up to 30 seconds, ending early if all players are ready.</p>
<p>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.</p>

<h1>Options</h1>

<p>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.</p>

<h2>Inverted <small>(default: off)</small></h2>
<p>Balance changes are negated.</p>

<h2>Simple <small>(default: off)</small></h2>
<p>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.</p>

<h2>Decks <small>(default: 1, min: 1, max: 9)</small></h2>
<p>Number of decks to use. 9 is treated as &infin; decks. Increases house edge.</p>

<h2>Dealer Hits on Soft 17 <small>(default: on)</small></h2>
<p>Dealer hits on soft 17 instead of standing. Increases house edge.</p>

<h2>Dealer Peek <small>(default: on)</small></h2>
<p>Dealer peeks and, after early surrender, ends the game immediately if there is a blackjack. Decreases house edge.</p>
<p>Typically on in American and off in European games.</p>

<h2>Double</h2>
<p>Doubling is allowed when the hand value is</p>
<ul>
  <li>any (default)
  <li>9 to 11
  <li>10 or 11
</ul>
<p>Later options increase house edge.</p>

<h2>Double After Split <small>(default: on)</small></h2>
<p>After splitting, allow doubling each hand separately. Decreases house edge.</p>

<h2>Surrender</h2>
<p>Surrendering is allowed when</p>
<ul>
  <li><strong>off</strong>: never
  <li><strong>late</strong> <em>(default)</em>: the dealer does not have a blackjack
  <li><strong>early non-ace</strong>: the dealer shows a non-Ace
  <li><strong>early</strong>: always
</ul>

<h2>Split Non-Ace <small>(default: 3, min: 0, max: 3)</small></h2>
<p>Pairs of 2 to 10 can be split N times to make N+1 hands. Decreases house edge.</p>

<h2>Split Ace <small>(default: 1, min: 0, max: 3)</small></h2>
<p>Pairs of aces can be split N times to make N+1 hands. Decreases house edge.</p>

<h2>Hit Split Ace <small>(default: on)</small></h2>
<p>Allow hitting split aces. Decreases house edge. If hit with a 10, the blackjack is not a "natural" blackjack.</p>