Rules Desk
Dealer stands on soft seventeen
A single line on the felt, and one of the larger arithmetic differences between two otherwise identical blackjack tables.
A soft hand is one containing an ace counted as eleven. A soft seventeen is therefore an ace with a six, or an ace with cards totalling six, and it cannot be broken by drawing one more card.
That is the whole basis of the rule. A hard seventeen is fragile: drawing to it risks going over twenty-one. A soft seventeen is not, because the ace can revert to counting one. Drawing to it costs nothing in immediate risk.
So a table where the dealer draws on soft seventeen gives the dealer a free attempt to improve a hand that would otherwise lose to any eighteen, nineteen, twenty or twenty-one. A table where the dealer stands takes that attempt away.
Neither version is unusual and both are ordinary rule sets, printed openly on the felt. The point is only that they are not the same game, and that the difference is invisible unless the panel is read.
The convention travels with other terms. A table that draws on soft seventeen frequently offsets it elsewhere in the printed rules, and a table that stands may be stricter about doubling or splitting. The panel is read as a whole or not at all.