A Closer Look at Basic Strategy

 A Closer Look at Basic Strategy

Some basic strategy players, like doubling 11 vs a five or six are fairly intuitive. We know these are dealer 'bust cards' and the most common card in a blackjack game is a ten. There is a 30% chance (4/13) you are going to end up with 21 after you double down on 11, and if you miss, hey the dealer can always bust. It makes logical sense that we would want to double our wager.

Although it is true the dealer busts more often with a 5 or 6 than any other total, even with these cards up they are still more likely to make a hand than to not.

Dealer Card	2	3	4	5	6	7	8	9	10	Ace
Bust %	35%	37%	40%	42%	42%	26%	24%	23%	23%	17%

It is also worthwhile to note that the dealer bust % on a 7 is 26%. This is an important number for one reason, specifically because standing on a stiff out preforms surrendering vs a 7 which is not the case vs 8 or above. Because surrender returns only half your bet, it is a -50% loss. So if you win 26% of the time, you are only generating -48% loss.

Or to put it this way, if you bet $10, and win 26% of the time, you will get $20 back 26% of the time for an EV of $5.20. This is greater than the EV of surrendering, which is $5.00.

Other blackjack plays are less intuitive, such as splitting 88 v T or doubling A7 v 2 in a H17 game.

It isn't important to understand these plays logically. All you need to do is memorize your basic strategy chart in order to be able to make the correct play. Trying to reason the whys and hows of basic strategy can be a fruitless endeavour. But at least with 88 v T, the logic of splitting is pretty clear. A hard 16 is a lousy total. It's the worst total you can have. Even a six will bust you! In fact any 6, 7, 8, 9, T, J, Q, or K will bust you. That's almost 2/3rds of the deck. And standing isn't any more appealing, since the dealer will make their hand around 77% of the time if they have a ten up.

Doubling A7 v 2 is an interesting play. In S17 this is right on the nose. Standing returns 0.121742 and doubling returns 0.119750. In H17 this becomes a basic strategy double, in part because the dealer will bust a little more often, but also because they won't necessarily stop on 17. If you have 18, you love it when the dealer stops on 17.

18 is a Hard Hand to Play

99 and A7 are two hands that people commonly misplay. The proper basic strategy for A7 is to double vs 2-6, stay vs 7 or 8, and hit vs 9, T, or A. 

For 99 you split vs 2-6, stay vs 7, split vs 8 and 9, and stay vs T-A.

The important take home lesson here is that 18 is not a great total. A lot of players get to 18 and think to themselves "well gee, we are past 17, we don't normally get up this high, better stay here". But the reality is in a lot of cases you have a higher expectation play available to you.

If you think about it, the dealer hits until 17. So with 18, you are hoping the dealer busts or makes 17. Otherwise you are pushing at best, and more likely to lose to a higher total. And when you have a soft 18, it is sort of a free hit. 

Sure, you could end up catching a 6 or 7, and then your situation got worse. But as we just established, it is not that much worse. You weren't in a great spot in the first place. And you still have another hit. In fact, if you catch a 4 or 5, you might even have two more hits.

If you catch an A, 2, or 3, then you just improved significantly.

If you catch a 10, J, Q or K, you are no worse off than before.

If you catch a 9, okay now you have 17. If the dealer gets 17 or 18 exactly, then you are worse off than before, but otherwise the situation is the same.

It's a marginal improvement to be sure, but it is an improvement.

Never Surrender?

Some people don't like to take advantage of the surrender play. They reason the casino wouldn't allow the rule if it didn't make them money. However, there are situations where surrender is the play with the highest expectation. Usually when you have 16.

16 v T, 9, and A are basic strategy surrenders.

15 v T is as as well.

In a H17 game, 15 and 17 also become basic strategy surrenders against A.

Surrender is actually a great rule. The impact for the basic strategist is mild, it only decreases the house edge by 0.09%. However, for a card counter the rule is more meaningful, as surrender increases in value during high counts. And it is in high counts that you raise your bet. Furthermore, surrender decreases the variance of blackjack, which is a good thing for a winning player.

Conclusion

Basic strategy can at times be counter intuitive. Make sure that you completely memorize basic strategy so that you don't make any errors, and you will maximize your chances of walking away a winner. And if you want to become a card counter, memorizing basic strategy is an important first step.