Basic strategy - problem?

Hi there,

I'm a new member - and I've just started trying to beat the house using basic strategy. I'm at the stage where I'm pretty comfortable with it and am starting to try to work in hilo.

But, I've noticed that on the wizard's really clear explanation there is what look like an inconsistency in the basic strategy.


--If you have a 14 versus a 10, basic strategy tells you to hit. Makes sense because you want to make 17.

--If you have 7,7 versus a 10, it tells you to stick... (!)

I understand these odds were created by 1bn runs on a computer and respect them for that but I've no idea why the odds would change in these two situations - can anyone enlighten me?


I was using all the standard filters.

1 Deck,
Dealer stands on soft 17
Double after split allowed
Surrennder not allowed
Dealer peeks for bj

Thanks,

TL

Your goal is to beat the dealer, not reaching 17 (actually 17 is a losing hand).

A huge chunk of the probability space to beat the dealer is to draw to 21. If you have 7,7 vs 10 you would need to draw a 7 to reach 21. However most of the 7s in the deck you already hold in your hand, especially in a single deck game (where you hold half of all 7s).

If you have a different 14 (i.e. 8+6) all four 7s are available in the deck to be drawn. This is why you would want to stand on 7,7 vs 10, but draw on any other 14.

This effect of card removal is only present in small number of decks, especially in single deck.

Hit it in negative counts.

FWIW, the 77 v T S play is only for single deck, not for multiple decks (including DD). As mentioned, this is due to the effect of removal of 7s in the deck. Since there are only 2 more 7s left to deal, the odds of making a 21 shrink dramatically.

As has been said the importance of hitting vs standing is your chances of getting 21 (and to a lesser extent 20). In single deck play, your cards have a large effect, especially 77, but also some 15s and most 16s. In multiple decks the effect of each individual card is less, so there need to be more out/gone to change from basic strategy. Usually this is simplified by mentioning "the count", so by and large it's correct to hit 14 in most 4 or more decks hands. There are some close decisions, e.g. 16vs10, 12vs4 etc. which do flip depending on cards gone.
Most "strategies" assume you can only see (and remember) cards you've got this hand and the dealer's upcard - hence single deck has some special cases that more decks don't tend to have.

deleted

I also have a basic strategy problem.
Even though I know that if I mastered the deviation chart, basic strategy decision doesn't matter anymore. But I wonder why every basic strategy engine on the internet shows that:
6 deck, Stand soft 17 game, A7 against 2, the basic strategy says to STAND.
But with 6 deck, Hit soft 17 game, A7 against 2, the basic strategy says to HIT.

However, the deviation number for both rules, A7 against 2, the index number is 0.

If the index is 0 for both rules, why is there a difference in Basic Strategy Charts, it doesn't make sense to me..
Can someone please explain?

As you see for the H17 and S17 game, both options are quite close in EV.

Keep in mind that no counting system could yield 100% playing efficiency. While the index 0 might not be perfect for A7 vs 2 (and no other cards seen), it might still be the best index for the overall game.

deleted

Quote: tweedlover

...I've just started trying to beat the house using basic strategy.