As in all casino games, the house has a statistical advantage over the players that will play itself out in the long run. But because blackjack, unlike other games, has an element of player choice, players can actually reduce the casino advantage to a small percentage by playing what is known as basic strategy. This strategy determines when to hit and when to stand, and also determines when doubling down or splitting is the correct action. Basic strategy is based on the player's point total and the dealer's visible card. There are slight variations in basic strategy depending on the exact house rules and the number of decks used. Under the most favorable conditions (single deck, downtown Las Vegas rules), the house advantage over a basic strategy player can be as low as 0.16%. Indeed, casinos offering special rules like surrender and double-after-split may actually be offering a positive expectation to basic strategy players; they are counting on players making mistakes to make money.

The following rules are beneficial to the player:

1. Doubles are permitted on any two-card hand except a blackjack.
2. Doubles are permitted after splitting.
3. Early surrender; the ability to forfeit half your wager against a face or ace before the dealer checks for blackjack.
4. Normal (aka "late") surrender.
5. Resplitting Aces.
6. Drawing more than one card against a split Ace.
7. Five or more cards with the total still no more than 21 as an automatic win (a "Charlie")

The following rules are detrimental to the player:

1. Less than 3:2 payout on blackjacks (6:5 and even 1:1 payouts have become common, especially in single-deck games, in Las Vegas since about 2003)
2. Dealer hits on soft seventeen (ace, six)
3. Splitting a maximum of once (to two hands)
4. Double down restricted to certain totals, such as 9-11 or 10,11
5. Aces may not be resplit
6. No-Peek (European) blackjack—player loses splits and doubles to a dealer blackjack
7. Player losing ties

This guide is licensed under the GNU Free Documentation License. It uses material from the Wikipedia.