What makes a 17 soft?
A hand is soft when an ace currently counts as 11 without making the total exceed 21. Ace-six is soft 17. Ace-two-four is also soft 17. If a ten is added, the ace falls to 1 and the resulting 17 is hard.
Under S17, the dealer stops on both soft and hard 17. Under H17, the dealer draws on soft 17 but stops on hard 17.
How to identify the table rule
Look for printed table text or a rule placard: “Dealer stands on all 17s” indicates S17; “Dealer hits soft 17” indicates H17. Do not infer the rule from the dealer’s behaviour in one hand. Online games should state it in their rules or help panel.
Third Base exposes the rule as a selector before the hand. Change it only between hands so feedback is graded against the intended table.
Third Base strategy changes
For the 4-, 6-, and 8-deck rules implemented here—3:2 blackjack, dealer peek, double after split, no surrender—the H17 selector changes these three two-card decisions when doubling is available:
| Player hand | Dealer | S17 | H17 |
|---|---|---|---|
| Hard 11 | Ace | Hit | Double |
| Soft 18 (A,7) | 2 | Stand | Double |
| Soft 19 (A,8) | 6 | Stand | Double |
If doubling is not available, the engine applies the relevant fallback. Other rule sets can contain different changes.
Why the chart changes
Letting the dealer draw on soft 17 changes the dealer’s final-total distribution. Basic strategy responds to that rule by changing a small number of close decisions. The direction of a change cannot safely be guessed from a general slogan; use a chart matched to all the game rules.
Practise the exceptions
- Set the trainer to S17 and practise hard 11 versus ace, A-7 versus 2, and A-8 versus 6.
- Switch to H17 and repeat the same hands.
- Use the strategy calculator for deliberate lookups.
- Return to mixed practice only after you can name both answers without a prompt.
Scope of this guide
The comparison describes the open-source Third Base table, not every blackjack game. Deck count, surrender, doubling restrictions, hole-card procedure, blackjack payout, and split rules can all change strategy. See Blackjack Rules Explained, the complete chart, and trainer methodology.