Blackjack

Introduction

Blackjack, also known as Twenty-one or Vingt-et-un (French for "twenty-one"), is a comparing-type card game which is the most widely played casino banking game in the world. The standard game is played with one or more French decks of 52 cards. The player draws cards to an initial two card hand with the object of bringing the total hand value as close as possible to 21 without exceeding it, so that the house, which plays after the player, will fail to get up to the player's total, or will lose by exceeding 21. Blackjack is played in many variations at casinos with different table rules. Much of blackjack's popularity is due to the mix of chance, skill, and the publicity that surrounds card counting, which entails adapting one's wager and playing strategy to the profile of cards yet to be dealt.

Rules and play

Blackjack hands are scored according to the sum of card values. For example, a hand composed of a 4, 5, and 6 is scored as 4+5+6=15. Face cards each have a value of 10. Aces can be valued as either 1 or 11, so an ace and 7 could be scored as either a 8 or a 18. The objective in blackjack is to have the highest card sum that does not exceed 21. A sum of greater than 21 is called a bust. If the player busts, he loses his bet, regardless of the dealer hand. A 2-card 21 is known as a "blackjack" and is the highest ranking hand. The player receives a bonus for having a blackjack. Blackjacks pay 3:2, while other wins pay 1:1.

After placing a bet, the player and dealer are each given two cards. One of the dealer's two cards is face up and visible to the player. Under standard rules, if the dealer has an ace or 10-point card showing, he will peek for a possible blackjack. If the dealer has an ace showing, the player has the opportunity to buy "insurance" against the blackjack. Insurance pays 2:1 if the dealer's remaining card is a 10 or face card to form a blackjack. With single-hand play, the house edge on the insurance bet of is 2-15%, depending on decks and cards played. So it is not to the player's advantage to buy insurance, excluding special situations in which the deck is known to be tens rich (multi-hand with 1-2 decks and few tens drawn, or card counting).Avoid insurance.

Player decisions

After receiving an initial two cards, the player has four standard options: "hit," "stand," "double down," or "split". Each option requires the use of a hand signal. At some casinos or tables, the player may have a fifth option, called a "surrender."

Hit: Take another card from the dealer.

signal: (handheld) Scrape cards against table. (face up) Tap the table or wave hand toward body

Stand: Take no more cards; also known as "stand pat", "stick", or "stay".

signal: (handheld) Slide cards under chips. (face up) Wave hand horizontally.

Double down (only available as first decision of a hand): The player is allowed to increase the initial bet by up to 100% in exchange for committing to stand after receiving exactly one more card. The additional bet is placed in the betting box next to the original bet. Some games do not permit the player to increase the bet by amounts other than 100%. Non-controlling players may double their wager or decline to do so, but they are bound by the controlling player's decision to take only one card.

signal: Place additional chips beside the original bet, and point with one finger.

Split (only available as first decision of a hand): If the first two cards have the same value, the player can split them into two hands, by moving a second bet equal to the first into an area outside the betting box of the original bet. The dealer separates the two cards and draws a further card on each, placing one bet with each hand. The player then plays out the two separate hands in turn, with some restrictions. In the case of ten-valued cards, some casinos allow splitting only when the cards have the identical symbols; for instance, a hand of T-T or K-K may be split, but not of T-K or K-T. Other casinos allow splitting of any pair of ten-valued cards. Doubling and further splitting of post-split hands may be restricted, and blackjacks after a split are counted as non-blackjack 21 when comparing against the dealers hand. Hitting split aces is usually not allowed. Non-controlling players may follow the controlling player by putting down an additional bet, or decline to do so, instead associating their existing wager with one of the two post-split hands. In that case they must choose which hand to play behind before the second cards are drawn.

signal: Place additional chips next to the original bet outside the betting box. Point with two fingers spread into a V formation.

Surrender (only available as first decision of a hand): Some games offer the option to "surrender." After the dealer has checked for blackjack, the player may "surrender", whereupon the house will take half the player's bet and return the other half to the player; this terminates the player's interest in the hand. The request to surrender is made verbally, there being no commonly accepted hand signal.

Side Bets

Avoid side bets!

Strategy   (IMPORTANT).

Print it or keep a window open with the table.

The table below shows optimal strategy for typical online casino rules.

House Edge
Aprox. -0,49%

Variance

Blackjack has a standard deviation per hand of ~1.14 and a standard deviation per wager of ~1.07 with typical online rules.