Play it right!

4 August 2019

By John Grochowski

On a Saturday evening in July, I joined longtime friend Matt for pizza and baseball, watching the Cubs and Brewers over some fine dining.

Matt doesn’t gamble, so I really didn’t expect to be debating blackjack strategy. But Rob, a friend of Matt’s I’d never met before, had been to a casino that morning and lost a few dollars.

Rob wanted to expound on the evils of hitting soft 18 against a dealer’s 9, 10 or 11 – the correct basic strategy plays.

“Basic strategy just seems so arbitrary,” he said. “Sometimes it just lacks common sense.”

There’s nothing arbitrary about basic strategy. It was calculated by considering every possible outcome of every possible play. It misses some fine points centered on hand composition, and advantage players can improve on it by adapting strategy to the count, but basic strategy is a solid guide to the best plays for most players.

“Hitting ace-7 just makes no sense at all,” Rob said. “You have 18. Why would you want to hit that?”

I told him hitting soft 18 against 9, 10 or ace improved your chances of winning. Against those up cards, soft 18 is a losing hand, but taking the chance to improve it helps reduce the losses.

“Well, I tried it against a 9, and what did I get? A 9,” Rob said. “I didn’t improve 18. I got worse at 17. And I lost the hand.”

Hitting soft 18 will win more often than standing on soft 18 against 9, 10 or 11, but certainly, every play backfires sometimes.

I didn’t get into all this with Rob. He seemed more in the mood for a good rant. But players should remember 18 is a less than spectacular hand. You can win if the dealer busts or has 17. You just push against a dealer 18, and the dealer beats you with 19 or higher.

In a common six-deck game in which the dealer hits soft 17, a dealer starting with 9 will bust 22.9% of the time and finish with 17 in 12% of hands. Those represent your wins if you stand on soft 18 and you’ll push the 11.7% the dealer gets to 18. But you lose on the 19 (35.2%), 20 (12%) and 21 (6.1%).

Starting with 10, dealer final hand proportions are 23% busts, 12.1 each for 18, 18 and 19, 36.8 for 20 and 3.8 for non-blackjack 21. Dealer blackjacks – 7.7% of hands starting with a 10 up – are excluded because they end the hand when the dealer checks for blackjack, so they don’t affect your playing strategy.

And with an ace, it’s 20.1% for bust, 8.3 for 17, 20.7 for 18, 20.7 for 19, 20.7 for 20 and 9.5 for non-blackjack 21s.

In each case, player losses when standing on soft 18 outweigh the wins.

Even hitting the soft 18, we can’t turn the hand into a winner, but we can cut the average losses. Let’s look at the numbers for each hand:

• Ace-7 vs. 9: Stand, and your average loss is 18.3 cents per dollar of your wager. Hit, and you cut that to 9.8 cents.


• Ace-7 vs. 10: Stand, and your average loss is 18.0 cents per dollar of your wager. Hit, and you cut that to 14.3 cents.


• Ace-7 vs. 9: Stand, and your average loss is 22.5 cents per dollar of your wager. Hit, and you cut that to 16.0 cents.

Hitting soft 18 may feel wrong, but the play is right against a dealer’s 9 or higher.

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