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# Blackjack Buffs Often Bungle Soft SEVENTEEN

15 May 1995

od blackjack players know that the best move with "hard" 17 is to stand, regardless of the dealer's upcard. "Soft" 17, with the total reached by counting ace as 11, is trickier. Stand? Double down? Hit? And when?

A 17 is weak. It loses more than it wins with any dealer upcard except six. Even then, it's favored by less than one net win in 100 hands.

To see why you stand on hard 17, despite its weakness, think of the thirteen different cards you might draw. Four (30.8 percent) improve your hand but don't guarantee a win; nine (69.2 percent) put you over 21 and make you an instant loser.

Never stand on soft 17, however. One or the other of the alternatives is always a better play.

Doubling down in blackjack involves making a second bet equal to or less than the first, after you've seen your initial hand, then drawing a single additional card. Two criteria for doubling are embodied in basic strategy. These ensure that you make the extra bet only when you're favored and that the expected profit exceeds that of drawing with the option to take more cards. 1) Double only when you're more apt to win than lose. 2) Double only when your advantage over the house is more than half that of hitting.

These criteria lead to doubling on soft 17 when the dealer shows three, four, five, or six. Here are the kinds of probabilities involved with the various choices, illustrated for a dealer's four-up.

Stand: Odds are that you'll win about 39.45 percent, tie 13.05 percent, and lose 47.50 percent. Your net disadvantage (losses minus wins) is 8.05 percent.

Double or hit: Either way, you'll only take one card. No matter what it is, you'll be between 12 and 21 and won't draw again to a four. Odds then are that you'll win roughly 48.9 percent, tie 8.0 percent, and lose 43.1 percent. This gives net advantage of 5.8 percent. It meets both doubling criteria because expectation is positive and the advantage equals so is over half that of hitting.

Doubling on soft 17 against two or seven through ace has negative expectation. This violates the first doubling criterion, and is a no-no. Net disadvantage is about 0.5 percent against two or seven, worse for stronger upcards.

Since you won't stand on soft 17 and should double on the first two cards for a dealer's three through six, you're left hitting on everything else. When you do, you can expect ace through four as your first card improving your position close to 30.8 percent of the time. A 10, which neither helps nor hurts, is also a 30.8 percent shot. The other 38.4 percent will drop the total to 12 through 16. This degrades your hand but doesn't lose instantly, and may still win. Overall, when the math is done, hitting soft 17 against two and seven through ace leaves you an underdog, but stronger than you'd be by standing.

Individual blackjack rules seem easy when you read them. They get tough when you're trying to remember them all at once and money at risk is heightening pressure during play. What then?

You can carry a basic strategy chart. Casinos let you use them and nobody will snicker. You can also ask. The dealer, or one of the players, will gladly tell you. Proficient players are used to rookies and would rather abet them than abide the bad breaks they believe brought by bum calls. As Sumner A Ingmark observed when helping to open the Riviera Casino in Havana Cuba many moons ago:

Smart gambling's an acquired skill,
That all can learn though some ne'er will
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Best of Alan Krigman
Alan Krigman

Alan Krigman was a weekly syndicated newspaper gaming columnist and Editor & Publisher of Winning Ways, a monthly newsletter for casino aficionados. His columns focused on gambling probability and statistics. He passed away in October, 2013.
Alan Krigman
Alan Krigman was a weekly syndicated newspaper gaming columnist and Editor & Publisher of Winning Ways, a monthly newsletter for casino aficionados. His columns focused on gambling probability and statistics. He passed away in October, 2013.