Most of the chart does not move
It surprises many learners that the great majority of basic strategy is the same at almost any table. Hard 8 hits, hard 17 stands, aces and eights split, tens do not. Rule differences affect a small number of borderline decisions, usually where the best action wins only narrowly over the next best.
So the practical approach is to learn the core chart first, then note the few changes that apply to the game in front of you. This article describes the main ones. How rules affect the size of the house edge, as opposed to which action is chosen, is a separate subject.
Dealer hits or stands on soft 17
This is the most common rule difference. A soft 17 is a hand such as ace and 6. Under the stand rule, the dealer stops. Under the hit rule, the dealer draws another card. The dealer’s drawing procedure is covered more fully in the soft seventeen article.
Hitting soft 17 helps the dealer slightly, since the dealer can improve and has less chance of finishing on a weak 17. Some of the strategy changes that follow are:
- Hard 11 against an ace: many charts hit under the stand rule (especially with several decks) and double under the hit rule.
- Soft 18 against a 2: stand under the stand rule, double under the hit rule.
- Soft 17 against a 2: hit under the stand rule, double under the hit rule.
- Soft 19 against a 6: stand under the stand rule, double under the hit rule.
- Surrender hands: where surrender is offered, a few more hands qualify against an ace, such as hard 15 and hard 17.
These are narrow differences and the expected value gap between the two actions is small in each case. Missing one is a minor error, not a disaster, but it is still worth knowing what table you are at.
Doubling after a split
Doubling after a split (often written DAS) lets you double down on a hand created by a split. It is a player-friendly rule, and it increases the value of splitting small pairs, since a hand that starts at 2, 3, 4 or 6 can be improved and then doubled.
With DAS, splits widen:
- Twos and threes split against a 2 or 3 as well as 4 through 7.
- Sixes split against a 2.
- Fours may split against a 5 or 6.
Without DAS, these splits are mostly dropped, and the pairs are played as hard totals or split only in the stronger spots. The nature of splitting itself is explained in the article on pair splitting.
Resplitting and split-ace limits
If you can resplit, a pair that is worth splitting is a little more valuable, since you can split again if you draw another card of the same value. Where resplitting is limited, or where split aces receive only one card, the value falls. These rules change the size of the benefit but rarely flip the decision for aces or eights, which remain splits, as discussed in the article on splitting aces and eights. More on these table limits appears in the resplit limits guide.
Surrender
When late surrender is available, there are a few hands where giving up half the bet is better than playing on, mainly hard 16 against a 9, 10 or ace, and hard 15 against a 10. The rule adds new decisions rather than changing old ones, and it is examined in its own article.
Number of decks
The number of decks changes a few cells, mostly because of how cards are removed from the shrinking pack. For example, a few doubles and splits that apply in single-deck games disappear in multi-deck games. These differences are small, and the multi-deck chart is a reasonable starting point for most tables. The effect of the number of decks on the odds is a related subject.
Payouts and other rules that do not change play much
A 6 to 5 payout on naturals, compared with 3 to 2, makes the game costlier but leaves the play decisions largely unchanged. The same is true of most side bets and bonus payouts. They change the price of playing rather than the best action. Other games with different rules are compared under blackjack variants.
How to use this
- Read the rules posted at the table, or on the online game’s rule screen.
- Note the dealer’s soft 17 rule, whether DAS is allowed, whether surrender is offered, and the number of decks.
- Use a chart that matches those rules, and mark the few cells that differ.
Following a chart that does not match the table is one of the quieter strategy errors, but the cost per decision is usually small.
Perspective
Matching strategy to the rules reduces unnecessary loss, but no rule set removes the house edge, and playing correctly does not make winning likely in any session. Gambling can be harmful, so keep to limits you can afford, and contact a local support service if you need help.