Lesson 15 – The Advanced Course – Part 3

Last Updated: February 18, 2020

Basic Strategy Variations: Double?

The opportunity to double your bet in return for agreeing to accept only one more card is a very powerful option for the player, if it’s utilized correctly. I can’t tell you how often I see players double hands like 7 or 8 against a dealer’s up card of 6 and then bemoan their fate when they lose. Yes, the dealer is very vulnerable with a 6 showing, but placing an extra bet changes the mathematics of the hand, so all doubles must be well-considered. For example, in a six-deck game where the dealer stands on A-6, doubling a hand of 8 against the dealer’s 6 has a total return of 10.3% whereas just hitting the hand returns 12.3% and the risk is lower!

That said, there comes a time when it is worthwhile to double an 8 against a dealer’s 6 and that’s when there’s a higher proportion than normal of 10s left in the deck. That point is determined, of course, by the true count. As the true count gets more positive, it becomes more profitable to double. Conversely, as the count goes negative, it becomes a better play to hit some hands, rather than double.

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Just as you’re using flashcards to learn the hit/stand variations, make up, a set for doubling. Here are the numbers you need:

Basic Strategy Variations Six decks, dealer stands on A-6

Note from the BlackjackInfo.com editor:

There are slight differences in the GameMaster’s index numbers published here and the optimized numbers on the
BlackjackInfo Advanced Blackjack Strategy Cards.

These differences are usually due to the use of risk-averse calculations by the GameMaster. I maintain that for the majority
of players (who are not playing near the maximum Kelly fraction of their bankroll), straight indexes are preferable to
risk-adjusted ones. In any case where risk-averse indexes differ from straight indexes, even by several points,
the decisions are quite close and the effect of choosing one index style over another is minimal.

Soft Doubling

A-2 vs. 4Double at 3.(Got this? Basic strategy says to HIT A-2 against a 4, but if the true count is 3 or higher, you should double.)
A-2 vs. 5Double at 0.(Don’t get confused here. Basic strategy says DOUBLE A-2 against a 5, but if the count is at all negative, just hit it; double only when the count is 0 or higher.)
A-2 vs. 6Double at -1.(or higher. As long as the count remains above -1, you’ll double; once it goes lower than -1, you’ll just hit — then hopefully leave the table if the count doesn’t improve.)
A-3 vs. 4Double at 1.
A-3 vs. 5Double at -1.
A-4 vs. 4Double at 0.
A-7 vs. 2Double at 1.
A-8 vs. 4Double at 5.
A-8 vs. 5Double at 2.
A-8 vs. 6Double at 1.
A-9 vs. 5Double at 6.
A-9 vs. 6Double at 5.

Hard Doubling

8 vs. 5Double at 6.
8 vs. 6Double at 3.
9 vs. 2Double at 2.
9 vs. 3Double at 0.
9 vs. 7Double at 6.
10 vs. 9Double at -2.
11 vs. ADouble at 1.


Make up a set of flashcards for these variations and begin working them into your game.

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Hello to everyone.last night i jump in a bj game that i was already counting with out playing.the numbers was very hot.rc +19 with 3 decks more to be played.on the table me and the dealer only.i make two bets of 20 euro each and the party begins.5 first card guess what !!! Faces and 10.so i have 20 and 20 and the dealer jas 10 and ….. he takes the ace!! Second round … again two boxes/bets of 15 euro and here we go again.i took 2 face cards in the first box second box an ace and an 8 and the dealer gets an ace !incurances he asks!!! And of course i put the bet.+3 tc i was calculate.and the hard time comes again … cards for the dealer again an ace (goodbye insurance)and an 9.a 9 !!!! 9 !!!! Total 21 !!! Just to loose and my bets and my incurance !!!that time i was so angry !!now i just see the maths.shit happens ?????

Jan Charles

I don’t really get why you should start doubling on an 11 vs the dealers A when the count is 1. Both you and the dealer basicly have an “11” so the count favours both equally. But you only get 1 extra card while the dealer can keep on hitting. Shouldn’t that give the dealer a little edge over you?

I know its not that important but im just curious why this starts becomming a profitable play. Is it maybe because the dealer busts more often?

Thanks and great work, love this site

Jan Charles

Oh and also, as the count gets bigger the dealer starts getting more Blackjacks which beats a regular “21” right?


Oh now i get it. Thanks men know I can sleep peacefully again 🙂


So , in a game where the dealer gets only 1 card and he draws the other one only after every player stands (kinda the same as the “no peek” i guess) , what should we do? Should we still double 11 against that dealer’s Ace ? Does this affects other decisions against Ace ?


ok but what about the advanced strategy, how can i adjust to the count? Like, should i still stand a soft 18 against dealer A at TC>1 ? and hard 14,15,16 against dealer A is still stand at TC> 9 , 9 , 8 ? or any other changes? you know better


I have a crazy question, I play, ” blackjack professional simulator “, by pepperdogsoft.com on my iPhone it is set for six decks, das, h17, surrender and da2 and at rather large true counts it tell me to double hard 12 v a dealer 2 as an I18 suggestion, I have won that a couple of times, but in all my reading I can’t find anywhere else that is suggested, have you ever heard of such a thing.? I thought you should hit 12 v 2 until true 3. Thanks


Thanks, I knew I wasn’t crazy, I thought the same thing you said, I would only ever do it I absolutely and positively knew my next card was a 9.


Are the numbers “running count” or “true count”,,,am a little bit connfused?


Do this Hi-Lo indexes apply with the European blackjack rules??
(no peek, dealer stands at soft 17, double any 2 cards, double after splits, no surrender, 4/6/8 decks)


Most of the deviation play amount to minute practical differences. For the vast majority of players would resources be best spent on focusing on a large enough kitty and supporting the psychology to contain a x10+ spread when normally you would play at best a x8 or x4 spread?


Thanks Ken. I’m just a poor student so I account for every dollar, as such I have a set amount set in stone as my bankroll. Thanks for the comments they are very helpful


I got into an argument with my dad about progressive loss betting systems. His argument was that in a casino where the minimum was extremely low and the maximum was extremely high the casino could be beat.

For example, say a casino offered a game with a 10 dollar minimum and a 1,310,720 dollar maximum (I know a casino would never offer this game but just assume they did for the purposes of the example). This would give you a 1-18 spread if you were to double your bet after every loss, not including splits and doubles. My dad argues that he could beat this casino because the chances of him losing 18 hands in a row is incredibly rare.

Assuming one plays perfect basic strategy the chances of losing this many hands in a row is approximately 1 in 262144. Is there a better way to explain this then to say that the potential small wins do not account for the possibility, however small it is, of losing 1,310,720 dollars.

Anyone have any ideas how I can convince my dad in an intelligent matter that he’s wrong?


Hello and thank you for this great website.
I play in France with 6 decks game and I am still in need for practise.

Just in relation with the message that talked about doubling your bet after each loss : is it right to consider you have 43% chances to win every single hand before it is dealt ?

In my mind, the chances of winning a hand depend on the true count just before that hand is dealt. Is it right to think so ? That is, when the true count is +2 for example you would have more chances to win a hand than when it is 0 ?


Thanks very much for your reply.

I am getting back to study and practice. Your lessons and exercises are very helpful, thanks for sharing all of this, because it makes us understand that it is not only people with a gift that can make it, but hard work and patience will pay off.

I have one more question if you don’t mind, please :

I read the French version of KO Blackjack. Do you agree with the fact that it is sufficient to keep the running count and not the true count to have the edge over the casino ?
I think I will start that way because it’s simpler.


Thanks for the detailed answer Ken its appreciated. I always thought counters played more aggressively than the kelly due the fact that extremely high counts are rare. It was my understanding then that it is best to get your max bet out at TC 4 or 5. Don Schlesinger for example plays an extremely aggressive spread where his units go up to two as the TC increases slightly. Is this not a normal betting spread for a counter? Do you recommend playing a half Kelly? Or is this all personal preference depending on how high you want your ROR to be.


Why do some of your indices differ from Wong’s when using the same benchmark rules? For example you that the index for a hard 8 v a 6 is a double at TC 3, whereas Wong says it is at TC 1. There are quite a few other examples that differ greatly from yours can you explain why.

Paul Flores

Here in the Mid-South and Gulf Coast – Dealers hit A,6 – they do not stand.

How does this process affect “doubling?”


Ken Smith, do you sell the individual advanced strategy card for 6 deck blackjack where the dealer hits on S17? I can’t find it as one of your individual cards and don’t have any interest in purchasing a full set of 6 to get 5 I don’t need.


I found it available on a different site. Thanks!

Michael Revaitis

I am a fairly successful speed count player switching over to the Hi Low system. I see that the Hi Low system is much more powerful system. In many of the variation decisions it is unclear in several cases if the count is true or running. Please advise if possible. Also I am an Atlantic City BJ player with 8 decks. Are the above rules almost the same as 6 decks?

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