Blackjack Strategy Trainer 21
The quick answer
| Pair | Basic strategy | Why |
|---|---|---|
| A,A | Always split | Each ace becomes a hand starting at 11 |
| 8,8 | Always split | Escapes hard 16, the worst total |
| 10,10 | Never split | 20 wins too often to break apart |
| 5,5 | Never split | Play it as hard 10 and double when correct |
| 9,9 | Split vs 2-6, 8-9; stand vs 7, 10, A | 18 is already good against dealer 7 |
| 7,7 | Split vs 2-7 | Turns hard 14 into two playable starts |
| 6,6 | Split vs 3-6, plus 2 if DAS | DAS makes the dealer 2 split worthwhile |
| 4,4 | Split only vs 5-6 with DAS | Otherwise hard 8 is better played as a hit |
| 3,3 and 2,2 | Split vs 4-7, plus 2-3 if DAS | Weak dealer cards and DAS create the value |
Always split cards
Aces and 8s are the two automatic splits. A,A is too weak together and too powerful apart. 8,8 is the opposite: the original total is awful, and splitting reduces the damage even against strong dealer cards.
Never split cards
Do not split 10s. A hard 20 is one of the strongest hands in blackjack and should be protected. Do not split 5s either. A pair of 5s is hard 10, which is a premium doubling hand against dealer 2 through 9 in standard rules.
The conditional cards
The middle pairs are where most mistakes happen. 9,9 is the most counterintuitive: split against dealer 9 but stand against dealer 7. 4,4 is also rule-dependent; it becomes a split only when Double After Split is allowed against dealer 5 or 6.
If the table does not offer DAS, tighten the low-pair splits. Without the chance to double after catching a good card, 2,2 vs 2, 3,3 vs 3, and 4,4 vs 5-6 lose much of their value.
Train the pair chart
The trainer drills pairs separately so the 9,9 and DAS exceptions come back until they stick.