Double.Why basic strategy says double
Hard 10 makes 20 with any ten-value card, and 20 beats nearly everything. Against a 9, that is worth a doubled bet.
Doubling ends the hand after one card. Add a bet equal to the original wager.
If the table restricts you: If doubling is not allowed, hit.
Engine explanation: Double with hard 10 against 9. This is a doubling situation: add an equal wager and receive exactly one card. This is a long-run basic-strategy decision, not a prediction of the next card.
Hard 10 against every upcard
H hit · S stand · D double · P split. Select a cell for its page.
Nearby hard totals against a 9
| Hand | Move | |
|---|---|---|
| Hard 5 | Hit | Why → |
| Hard 6 | Hit | Why → |
| Hard 7 | Hit | Why → |
| Hard 8 | Hit | Why → |
| Hard 9 | Hit | Why → |
| Hard 10 | Double | Why → |
| Hard 11 | Double | Why → |
| Hard 12 | Hit | Why → |
| Hard 13 | Hit | Why → |
| Hard 14 | Hit | Why → |
| Hard 15 | Hit | Why → |
| Hard 16 | Hit | Why → |
| Hard 17 | Stand | Why → |
| Hard 18 | Stand | Why → |
| Hard 19 | Stand | Why → |
| Hard 20 | Stand | Why → |
Training rules: six decks · dealer stands on soft 17 · no surrender
This is a separate educational profile. Rules can differ between app tables and other games.
- Six decks. Dealer stands on all 17s, including soft 17.
- US hole card and peek: decisions assume the dealer has checked and does not have blackjack.
- Double any first two cards, including after splitting. Doubling ends the hand after one extra card.
- Split equal card values into at most four hands. Split aces receive one card each; no resplitting aces.
- No surrender. A natural blackjack pays 3:2; 21 after splitting is not a natural.
- Total-dependent strategy. No card counting or expected-value estimates.
Profile six-deck-s17-das · rules 1.0.0 · strategy 1.0.0. The trainer asks for one decision per hand; it does not simulate wagers or settlement.