S17 vs H17 Blackjack
What “dealer stands/hits on soft 17” means and why it changes the game.
S17 means the dealer stands on soft 17; H17 means the dealer must hit it. Under the cited benchmark, H17 reduces player expected return by about 0.22 percentage points.
What is a soft 17?
A soft 17 is a 17 containing an ace currently counted as 11, such as A-6. Because the ace can fall to 1 if another card is drawn, the dealer can hit without immediately risking a normal hard-17 bust.
Why H17 helps the house
Hitting soft 17 can sometimes improve the dealer hand. Although it also creates some busts, the net effect under standard blackjack structures is unfavorable to the player.
Strategy changes too
Some doubles and surrender decisions differ between S17 and H17. This is why strategy tables must identify the dealer soft-17 rule.
Where to look
Online blackjack usually states S17 or H17 in rules/help, sometimes in longer language such as “dealer hits soft 17.”