All Those Little Blackjack Mistakes Add Up

I just returned from a Caribbean cruise. One of the men at our evening dinner table was also a frequent blackjack player in the casino, and I mentioned I had written a blackjack book.

So, one morning, the two of us kicked back out on the sun deck, and discussed various strategy points of the game. I had already seen him make the mistakes of a typical player, and he wanted to know what was wrong with them. Here's what we covered.

Even Money: Our first topic was taking Even Money on blackjack against an Ace, which he had always done. I explained that when the dealer has an Ace up against your blackjack, she's got almost exactly 4 chances out of 13 to have a 10 in the hole.

So, say you bet $20 and have blackjack against an Ace 13 times. If you always take Even Money, you'll collect $20 all 13 times for a total payoff of $260. But if you just let it go, you'll push those 4 times the dealer has the 10 underneath – then get paid $30 the other 9 times for a net payoff of $270. This is just a sample cross-section of how you'll do each way with all those blackjacks over your lifetime.

Although the difference boils down to a little less than a dollar per hand at these stakes, you'll generally be dealt about 85 hands per hour. This is only one mistake. It's typical for a $20 bettor to throw away $20 per hour in pure mistakes. Now here's another one.

11 against a Face: This fellow didn't double down with 11 if the dealer showed a 10. Fact is, if you just hit your 11 against a 10 up, you'll go 39/31 after you have this hand 70 times (adjusting for pushes). But if you double down and buy a small card, you'll be stuck standing on a "stiff" (12 through 16). Perhaps surprisingly, that'll only reduce your overall won/lost record to 38/32.

Now think it over. Winning 39 and losing 31 at $20 apiece earns $160 net. Winning 38 and losing 32 at $40 each earns $240. That's 50% more net profit on the fourth best starting hand you can ever be dealt. But it's only the fourth best hand if you optimize all its potential.

Ace/Tiny vs. Tiny: Like most players, he also didn't differentiate between hands like A/3 against a 3 -- and A/6 against a 6. He just doubled them all. I explained the key difference.

When you take one hit to any hand from A/2 through A/5, there are only 5 cards out of 13 that will give you a "made" hand (17 through 21). With A/2 for example, the only cards that would help you are a 4, 5, 6, 7 or 8. With the other eight cards, you'll be stuck holding a stiff, needing a dealer bust.

But when you have A/6 or A/7, it's exactly reversed. Now you'll make a completed hand 8 times out of 13 (check for yourself). Since you won't need a dealer bust nearly as often, you should double down much more aggressively with A/6 and A/7 (do it against any 3, 4, 5 or 6). But with the "Ace/Tiny" hands like A/2 or A/3, you need the dealer to be showing her very weakest up-cards (5 or 6). As a simple guide, you can just remember this rule of thumb; Ace/Tiny against a Tiny is a bad double.

12 against a "13": Here's a misnomer that gets most players into a world of trouble, including my new friend. Incorrectly assuming the dealer has a 10 in the hole, they look at their 12 against a 3 and call it "12 against a 13".

If the dealer really did have 13, then yes, you should really stand. The problem is that, in reality, the dealer will have some other card in the hole roughly 70% of the time. If you stand, you'll need a dealer bust –- or you're dead. And with a 3 up, the dealer busts just 37% of the time. Hit that hand.

Fix these and the other slew of mistakes you're probably making, and you'll save one whole bet an hour, on average.