You hold a hard 10 (no ace counted as 11) and the dealer shows a 9. Below is the correct basic-strategy decision computed by the Blackjack Theorem engine, and how it shifts with the table rules.
| Hard | 8 | 9 | 10 |
|---|---|---|---|
| 9 | H | H | H |
| 10 | Dh | Dh | H |
| 11 | Dh | Dh | Dh |
Dealer upcard across the top. The outlined cell is the hand on this page.
Double is correct with a neutral shoe. If you count cards, the play flips to hit at a true count of -3 or lower.
The two plays are 2.77 points apart with a neutral shoe. That is a wide enough margin that it takes a true count of -3 — a genuinely ten-poor shoe — to close it.
Computed by the engine for a full six-deck shoe. The true-count column comes from the same count-dependent table that powers the strategy charts.
| Table rules | Correct play |
|---|---|
| 6-Deck · S17 · DAS | Dh Double if allowed, else Hit |
| 6-Deck · H17 · DAS | Dh Double if allowed, else Hit |
| 6-Deck · S17 · DAS · Surrender | Dh Double if allowed, else Hit |
| 2-Deck · S17 · DAS | Dh Double if allowed, else Hit |
| 8-Deck · H17 · DAS | Dh Double if allowed, else Hit |
The mathematically correct play is: double if allowed, else hit. This is for 6-deck, dealer stands on soft 17, DAS. It can change with other rules (see the table).
It can. The table above shows the play under both S17 and H17 so you can match your exact table.
Yes. With a neutral shoe the play is double, and it flips to hit at a true count of -3 or lower. The two plays sit 2.77 points apart at a full six-deck shoe, which is why a modest change in the count is enough to reverse them.
