A soft 18 is A,7 — an Ace counted as 11 plus 7. Here is the correct basic-strategy play against each dealer upcard (6-deck, S17, DAS).
| Dealer | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | A |
|---|---|---|---|---|---|---|---|---|---|---|
| Play | S | Ds | Ds | Ds | Ds | S | S | H | H | H |
S = stand · H = hit · D = double · Ds = double if allowed else stand
See the row above for the correct play against each dealer upcard. It's for 6-deck, dealer stands on soft 17, DAS.
A soft hand contains an Ace counted as 11, so it can't bust on the next card. Soft 18 is A,7.