The rule
You split a pair, draw to one of the new hands, and it becomes a total worth doubling. Whether you may is a house rule, abbreviated DAS on the felt.
Removing it costs +0.132 percentage points, from 0.515% to 0.647%.
Why it changes splitting decisions
This is the part that surprises people. Some pairs are worth splitting only because of what you can do afterwards.
4,4 is the clearest case. A pair of fours is a hard 8, a perfectly playable hand. Splitting it makes two hands starting on 4, each of which will often draw to 9, 10 or 11 and want to double. With DAS you split against a dealer 5 or 6; without DAS you do not split at all.
2,2, 3,3 and 6,6 shift the same way at the margins, and the full chart on our basic strategy page assumes DAS is allowed.
Reading the table
DAS is usually printed on the layout or noted on the table placard. It is worth about a fifth of what the blackjack payout is worth, so check the payout first and this second.
Frequently Asked Questions
- What does DAS mean?
- Double After Split: you may double a hand created by splitting a pair.
- How much is it worth?
- 0.13 percentage points. Losing it takes the edge from 0.52% to 0.65%.
- Which splits does it change?
- 4,4 most clearly: split it against a 5 or 6 with DAS, never without. 2,2, 3,3 and 6,6 shift at the margins.
- Is it more important than the blackjack payout?
- No. A 6:5 payout costs 10.2 times as much.
Every figure on this page is computed by an expected-value engine that plays the game out: it derives the dealer's final-total distribution by recursion, evaluates standing, hitting, doubling and splitting at each decision, and takes the best. Rule costs are measured by re-running the whole calculation with the rule changed, not by quoting a published delta. The model assumes independent card draws, which sits a few hundredths of a percent from an exact shoe analysis; the rule differences it produces match published values. Rules vary by table, so read the felt.