You're dealt a pair of 9s. The dealer shows a 6. Split or play it as one hand? Basic strategy answers:
| Split ← | +0.4434 |
| Stand | +0.2834 |
| Hit | -0.6075 |
| Double | -1.2150 |
| You bust on the next card | 76.9% |
| Dealer 6 busts | 42.3% |
Split is not close: it beats Stand by 0.1599 per unit. Getting this one wrong costs $1.60 on a $10 bet, every single time. Across the 340 situations in this chart it ranks 55th by expected value — better than 285 of them, worse than 54. Expected value is per unit staked, computed for multi-deck, dealer stands on soft 17, double after split allowed. The model and the code are published as data.
Against a dealer 6 (42% bust chance), splitting 9s turns one mediocre total into two playable hands while the dealer is vulnerable. With double-after-split allowed, you also keep the option to press each new hand — that's where the split profit comes from.
Note the famous 9-9 exception: against a 7 you stand, because your 18 beats the dealer's likely 17. Against 8 or 9 you split again. It's the trickiest row of the whole chart.