FAQs

Why is blackjack different from other casino games ?

What is basic strategy ?

How to use the basic strategy table ?

What is card counting ?

How to count cards ?

Is card counting legal ?

How to use deviation index tables ?

How to use surrender index tables ?

What are balanced and unbalanced systems ?

What is a betting spread ?

Hi-low ?

KO ?

reKO ?

What is penetration ? and why is it important ?

Should I play 1 or more hands?

How do rules impact my advantage ?

When you play roulette in a casino, each spin is entirely independent from the previous ones. You have no way to predict what the next number will be based on the previous results. The casinos are more than happy to tell you the percentages of red/black, odd/even, hi/low, tiers/orphelins/voisins, columns/dozens and all the statistics you can imagine because they are utterly useless.

Thinking that after 10 reds in a row, a black has more chances to come is a common misconception, it even has a name, it is called the gambler's fallacy.

The reason why blackjack is different from roulette (or craps, oasis poker, brag, ...) is because it is a dependent trial game. The card which have already been dealt are discarded and are not in the deck anymore. It therefore changes the composition of the deck.

Let's take an example, tens are very good for the player and you have 96 of them at the beginning of a 6 decks shoe (312 cards), that is about 31% of the cards. If after a few rounds, 2 decks have been dealt and only 10 tens have been dealt, then there are 86 left in a 4 decks shoe (208 cards), that is about 41% of the cards and the player is now playing with an advantage. If the player is able to spot these advantage periods, he can bet bigger when he has an advantage, and smaller (or not at all) when he has a disadvantage. This give him an overall advantage over the house.

And this is what card counting is all about, betting bigger when you have the advantage.

As defined by Stanford Wong in Professional Blackjack, "Basic strategy is the best way to play a blackjack hand on the first round after a shuffle, assuming you see no cards other than your own and the dealer's upcard. For a person who does not count cards, basic strategy is the best way to play every hand".

A typical player who does not know the basic strategy can be playing with a very big disadvantage of 2% to 5%. When following the basic strategy, you can reduce the edge of the casino to its minimum. Depending on the combination of rules, the advantage of the casino then drops to about 0.5%.

How was basic strategy calculated ?

All the possible moves (hit, stand, split, double, surrender) have been simulated for every possible combinations of player's hand and dealer's upcard. From these results where determined the expected value of all of them (i.e. how much one is expected to win on average).

For each case, the moves with the best expected value have been qualified for the basic strategy.

As an example, let's take the hand 12 Vs 2. You can either hit, stand, double or surrender.

Hit has an expected value of -0.252

Stand has an expected value of -0.296

double has an expected value of -0.504

surrender has an expected value of -0.5

Hitting has the best expected value (even if it is a negative one) and therefore it is the correct move.

For a complete study of the basic strategy see Basic Blackjack or Professional Blackjack by Stanford Wong.

The basic strategy table is divided in 3 parts, one for hard hands, one for soft hands and one for split hands.

Select on the left the line corresponding to your cards total, and on the top the column corresponding to the dealer's up card.

The intersection gives you the right move.

S is for Stand

H is for Hit

D is for Double

Sp is for Split

Su is for Surrender

You can have cases where you get 2 moves, that means that you have to do the first one, unless it is impossible, in which case you have to do the second one.

An example would be if your cards are 2, 3 and 5 (for a total of 10) against an 8. The table says Dh, this means Double or Hit if Double is not possible. You have 3 cards and can not Double, therefore you should Hit.

During a blackjack game, the odds of the player winning the next hands change and fluctuate from negative to positive. This is due to the fact that high cards (aces and 10s) benefit the player more than the dealer, while the low cards, (especially 4s, 5s, and 6s) help the dealer while hurting the player. The more high cards remaining in the deck, the better for the player. This comes mainly from the following reasons:

- when there are more high cards, the player has more chances to hit a Blackjack (paid 3:2).

- when there are more high cards, the dealer has more chances to bust as he has to hit on stiff hands (12 to 16).

- when there are more high cards, The player will more often make a good score when doubling his hands.

- when there are more low cards, the dealer has more chances to make a hand and busts less often.

Card counting is a "simple" way to track the concentration of remaining high cards. By assigning a positive value to low cards and a negative value to high cards, the counter is able to accurately determine this concentration and can therefore know if he is playing with an advantage or not. This does not require supernatural abilities (more like a lot of concentration) as it usually mainly consist in adding and subtracting 1 to a "running count". The higher this count, the better for the player.

Depending on the count, the player can bet more (on high counts) or less (on low counts) according to a pre-calculated betting spread.

For more, see How to count cards ?

When you want to count cards, you have to use a system. A system helps you keep the count of the discarded cards, and helps you determine the density of high cards remaining in the deck.

The low cards are assigned a positive value (because it is good for the player when they come off the shoe) and the high cards are assigned a negative value (because it is bad for the player when they come off the shoe). Every time you see a card, you add its value to a running count.

The higher the running count, the more high cards remain in the shoe and therefore the better it is for the player. The system tells you above what value of that count the advantage switches from the bank to the player.

The basic strategy assumes you can only see your cards and the dealer's card. But by tracking the density of high and low cards remaining in the shoe, the system can refine the strategy and tell you when to deviate from it. An example would be 16 Vs 10. The basic strategy says to Hit, but if you count cards and know that there are more high cards than low cards left you should deviate and Stand. All these deviations are listed in the deviation and surrender index tables.

And finally, the system tells you how much to bet according to the count.

There are many different count system, they range from simple to awfully difficult. You can find a detailed list on Donald Schlesinger's card counting comparison chart

Counting cards using only your mind is legal. Using an electronic device to assist you, like a computer or cell phone is illegal.

The problem however is that most casinos are private clubs and they can ban you without having to give a reason. So if you get caught (or even just suspected of) counting cards, they may ask you to leave and not allow you to come again.

Index tables indicate whether you should follow the basic strategy or deviate from it based on the current count.

They are used in the same way as the basic strategy tables. You will either find an empty cell or a number.

If the cell is empty, just follow the basic strategy. If the cell has a number in it, it means that you might have to deviate from the basic strategy.

The rule is as follow :

- if the count is superior or equal to the index, either Stand, Double or Split

- if the count is inferior to the index, either Hit, do not Double or do not Split

which one of the 3 possibilities you choose depend on the case but it should be quite obvious if you know and understand well the basic strategy.

Let's have a few examples :

- Assuming you use the KO system, the running count is +5, you have 12 and the dealer shows a 3.

The index for 12 Vs 3 is +4, the running count is superior to the index so we should either Stand, Double or Split. As we can't split and are surely not going to double a 12 we should then Stand.

It is quite easy to understand that with a higher count and therefore more tens in the deck we prefer to stay because we have more chances to bust if we hit.

- Assuming you use the high-Low system now, the true count is -2, you have 12 and the dealer shows a 5.

The index for 12 Vs 5 is -1, the true count is inferior to the index so we should either Hit, do not Double or do not Split. The basic strategy was not saying to double or split therefore we will go with the 3 option and Hit.

It is quite easy to understand that with a lower count and therefore less tens in the deck we prefer to hit and try to make a score because we have less chances to bust if we hit.

- Assuming you use the reKO system now, the true count is +4, you have a soft 19(A8) and the dealer shows a 6.

The index for soft19 Vs 6 is 2, the running count is superior to the index so we should either Stand, Double or Split. With a higher count and therefore more tens in the deck we like to put more money on the table against a 6 and we Double.

Surrender tables indicate whether you should surrender your hand or play it.

They are used in the same way as the basic strategy tables. You will either find an empty cell or a number.

If the cell is empty, just follow the basic strategy. If the cell has a number in it, it means that you might have to deviate from the basic strategy and surrender.

The rule is lot more simple than with the deviation index table, just surrender if the count is superior or equal to the surrender index, apply basic strategy if the count is inferior.

An example would be with High-Low count, you hold 15 against a dealer's 9, the count is +4. The surrender index for this case id +2 therefore you should surrender. Don't even look to what the basic strategy says, just surrender.

Counting systems fall into two categories, the balanced ones and the unbalanced ones.

- Unbalanced systems keep a running count and base their decisions on it alone. They usually start their count with a very negative value (around -20).

- Balanced systems also keep a running count but before taking any decision, they require that you convert this running count into a true count.

The true count is the running count divided by the number of decks remaining in the shoe. The True count is therefore positive if there are more high cards and negative if there are more low card in remaining in proportion in the deck. All the decisions are based on the True count.

On the side of the unbalanced systems, they are easier to use because you don't have to convert to the true count for every decision. And they are as effective as the balanced ones.

On the side of the balanced systems, you don't have to count very negative values, and they are easier to adapt to more advanced strategies. With some training it is not difficult to calculate the true count. They also do better than unbalanced ones against single deck.

Which system you choose is a matter of taste, the more comfortable you are with it, the less errors you will make.

When counting cards you try to identify these periods when you have an advantage over the bank so you can bet bigger. If you flat bet (betting always the same amount) you can not take any advantage of it and it is totally pointless to count cards to start with.

The essence of card counting is to bet bigger when you have the advantage, but how bigger should you bet when you have 0.5% or 2% ?

There is a mathematical formula to calculate the exact amount you should bet in accordance to your bankroll and the advantage you have on the bet. This formula is the Kelly criterion.

The betting spread tells you how much you should bet for every count. It is system dependent as the different counts mean different advantages for each system.

For High-low a betting spread example would be

Bet 1 unit when counts <= 0

Bet 2 units when counts = +1

Bet 4 units when counts = +2

Bet 8 units when counts = +3

Bet 16 units when counts >= +4

It should be noted that for such a betting spread, you should have a bankroll of**at least** 3000 units. The bigger the bankroll, the smaller the chances to loose it all.

High-Low is a very famous balanced card counting system used by the MIT blackjack teams.

The card value tags are as follow :

Aces and Tens : -1

9, 8, 7 : 0

6, 5, 4, 3, 2 : +1

The reference book on the subject is Stanford Wong's Professional Blackjack.

KO is a very famous unbalanced card counting system. It stands for "Knock-Out"

The card value tags are as follow :

Aces and Tens : -1

9, 8 : 0

7, 6, 5, 4, 3, 2 : +1

The reference book on the subject is Olaf Vancura and Ken Fuchs's Knock-Out Blackjack: The Easiest Card-Counting System Ever Devised (Gambling Theories Methods).

reKO is a more recent unbalanced card counting system. It is in fact a simplified version of (the already simple) KO system. It stands for "really (ridiculously) easy KO"

The card value tags are as follow :

Aces and Tens : -1

9, 8 : 0

7, 6, 5, 4, 3, 2 : +1

The reference book on the subject is Norm Wattenberger's online book Modern Blackjack

The penetration is the percentage of cards which are dealt from the shoe.

If 3 decks are dealt out of a 6 decks shoe before the shoe is shuffled, the penetration is 50%.

If 5 decks are dealt out of a 6 decks shoe before the shoe is shuffled, the penetration is 83%.

To put it simply, the bigger the penetration, the more you will be in presence of high counts and therefore in high advantage situations.

The penetration is so important that a shoe with a 50% penetration is barely playable.

When looking for a blackjack table with the intention of counting cards (which should always be your intention) you should avoid these low penetration shoes and look for better ones, 75% or more is highly recommended.

Let's cut short on this one, always play 2 hands.

As the Blackjack in color's graph shows it, the best is to always play 2 hands.

The rules of the game changes the edge of the bank. That is the edge for a player not counting the card, it also offsets the advantage a card counter will have. As an example, if a card counter can expect an overall 2% advantage over a break even game, it will only have a 1.5% advantage over a game presenting a -0.5% bank edge.

"Blackjack forum online" provides a list of rules and their impact.

All the given percentage are relative to a game with 1 decks, dealer stands on soft 17 (S17), player can double any two cards (DOA), player may double after split (DAS). This game being about break even, house edge = 0%

For example, let's take the following set of rules :

6 decks (-0.54%)

dealer has a hole card (+0%)

dealer stands on 17 (+0%)

double after split allowed (+0%)

late surrender (+0.08%)

This game would give a 0.46% edge to the bank. This is the typical edge you will find.

Why is blackjack different from other casino games ?

What is basic strategy ?

How to use the basic strategy table ?

What is card counting ?

How to count cards ?

Is card counting legal ?

How to use deviation index tables ?

How to use surrender index tables ?

What are balanced and unbalanced systems ?

What is a betting spread ?

Hi-low ?

KO ?

reKO ?

What is penetration ? and why is it important ?

Should I play 1 or more hands?

How do rules impact my advantage ?

Why is blackjack different from other casino games ? |
Back |

When you play roulette in a casino, each spin is entirely independent from the previous ones. You have no way to predict what the next number will be based on the previous results. The casinos are more than happy to tell you the percentages of red/black, odd/even, hi/low, tiers/orphelins/voisins, columns/dozens and all the statistics you can imagine because they are utterly useless.

Thinking that after 10 reds in a row, a black has more chances to come is a common misconception, it even has a name, it is called the gambler's fallacy.

The reason why blackjack is different from roulette (or craps, oasis poker, brag, ...) is because it is a dependent trial game. The card which have already been dealt are discarded and are not in the deck anymore. It therefore changes the composition of the deck.

Let's take an example, tens are very good for the player and you have 96 of them at the beginning of a 6 decks shoe (312 cards), that is about 31% of the cards. If after a few rounds, 2 decks have been dealt and only 10 tens have been dealt, then there are 86 left in a 4 decks shoe (208 cards), that is about 41% of the cards and the player is now playing with an advantage. If the player is able to spot these advantage periods, he can bet bigger when he has an advantage, and smaller (or not at all) when he has a disadvantage. This give him an overall advantage over the house.

And this is what card counting is all about, betting bigger when you have the advantage.

What is basic strategy ? |
Back |

As defined by Stanford Wong in Professional Blackjack, "Basic strategy is the best way to play a blackjack hand on the first round after a shuffle, assuming you see no cards other than your own and the dealer's upcard. For a person who does not count cards, basic strategy is the best way to play every hand".

A typical player who does not know the basic strategy can be playing with a very big disadvantage of 2% to 5%. When following the basic strategy, you can reduce the edge of the casino to its minimum. Depending on the combination of rules, the advantage of the casino then drops to about 0.5%.

How was basic strategy calculated ?

All the possible moves (hit, stand, split, double, surrender) have been simulated for every possible combinations of player's hand and dealer's upcard. From these results where determined the expected value of all of them (i.e. how much one is expected to win on average).

For each case, the moves with the best expected value have been qualified for the basic strategy.

As an example, let's take the hand 12 Vs 2. You can either hit, stand, double or surrender.

Hit has an expected value of -0.252

Stand has an expected value of -0.296

double has an expected value of -0.504

surrender has an expected value of -0.5

Hitting has the best expected value (even if it is a negative one) and therefore it is the correct move.

For a complete study of the basic strategy see Basic Blackjack or Professional Blackjack by Stanford Wong.

How to use the basic strategy table ? |
Back |

The basic strategy table is divided in 3 parts, one for hard hands, one for soft hands and one for split hands.

Select on the left the line corresponding to your cards total, and on the top the column corresponding to the dealer's up card.

The intersection gives you the right move.

S is for Stand

H is for Hit

D is for Double

Sp is for Split

Su is for Surrender

You can have cases where you get 2 moves, that means that you have to do the first one, unless it is impossible, in which case you have to do the second one.

An example would be if your cards are 2, 3 and 5 (for a total of 10) against an 8. The table says Dh, this means Double or Hit if Double is not possible. You have 3 cards and can not Double, therefore you should Hit.

What is card counting ? |
Back |

During a blackjack game, the odds of the player winning the next hands change and fluctuate from negative to positive. This is due to the fact that high cards (aces and 10s) benefit the player more than the dealer, while the low cards, (especially 4s, 5s, and 6s) help the dealer while hurting the player. The more high cards remaining in the deck, the better for the player. This comes mainly from the following reasons:

- when there are more high cards, the player has more chances to hit a Blackjack (paid 3:2).

- when there are more high cards, the dealer has more chances to bust as he has to hit on stiff hands (12 to 16).

- when there are more high cards, The player will more often make a good score when doubling his hands.

- when there are more low cards, the dealer has more chances to make a hand and busts less often.

Card counting is a "simple" way to track the concentration of remaining high cards. By assigning a positive value to low cards and a negative value to high cards, the counter is able to accurately determine this concentration and can therefore know if he is playing with an advantage or not. This does not require supernatural abilities (more like a lot of concentration) as it usually mainly consist in adding and subtracting 1 to a "running count". The higher this count, the better for the player.

Depending on the count, the player can bet more (on high counts) or less (on low counts) according to a pre-calculated betting spread.

For more, see How to count cards ?

How to count cards ? |
Back |

When you want to count cards, you have to use a system. A system helps you keep the count of the discarded cards, and helps you determine the density of high cards remaining in the deck.

The low cards are assigned a positive value (because it is good for the player when they come off the shoe) and the high cards are assigned a negative value (because it is bad for the player when they come off the shoe). Every time you see a card, you add its value to a running count.

The higher the running count, the more high cards remain in the shoe and therefore the better it is for the player. The system tells you above what value of that count the advantage switches from the bank to the player.

The basic strategy assumes you can only see your cards and the dealer's card. But by tracking the density of high and low cards remaining in the shoe, the system can refine the strategy and tell you when to deviate from it. An example would be 16 Vs 10. The basic strategy says to Hit, but if you count cards and know that there are more high cards than low cards left you should deviate and Stand. All these deviations are listed in the deviation and surrender index tables.

And finally, the system tells you how much to bet according to the count.

There are many different count system, they range from simple to awfully difficult. You can find a detailed list on Donald Schlesinger's card counting comparison chart

Is card counting legal ? |
Back |

Counting cards using only your mind is legal. Using an electronic device to assist you, like a computer or cell phone is illegal.

The problem however is that most casinos are private clubs and they can ban you without having to give a reason. So if you get caught (or even just suspected of) counting cards, they may ask you to leave and not allow you to come again.

How to use deviation index tables ? |
Back |

Index tables indicate whether you should follow the basic strategy or deviate from it based on the current count.

They are used in the same way as the basic strategy tables. You will either find an empty cell or a number.

If the cell is empty, just follow the basic strategy. If the cell has a number in it, it means that you might have to deviate from the basic strategy.

The rule is as follow :

- if the count is superior or equal to the index, either Stand, Double or Split

- if the count is inferior to the index, either Hit, do not Double or do not Split

which one of the 3 possibilities you choose depend on the case but it should be quite obvious if you know and understand well the basic strategy.

Let's have a few examples :

- Assuming you use the KO system, the running count is +5, you have 12 and the dealer shows a 3.

The index for 12 Vs 3 is +4, the running count is superior to the index so we should either Stand, Double or Split. As we can't split and are surely not going to double a 12 we should then Stand.

It is quite easy to understand that with a higher count and therefore more tens in the deck we prefer to stay because we have more chances to bust if we hit.

- Assuming you use the high-Low system now, the true count is -2, you have 12 and the dealer shows a 5.

The index for 12 Vs 5 is -1, the true count is inferior to the index so we should either Hit, do not Double or do not Split. The basic strategy was not saying to double or split therefore we will go with the 3 option and Hit.

It is quite easy to understand that with a lower count and therefore less tens in the deck we prefer to hit and try to make a score because we have less chances to bust if we hit.

- Assuming you use the reKO system now, the true count is +4, you have a soft 19(A8) and the dealer shows a 6.

The index for soft19 Vs 6 is 2, the running count is superior to the index so we should either Stand, Double or Split. With a higher count and therefore more tens in the deck we like to put more money on the table against a 6 and we Double.

How to use surrender tables ? |
Back |

Surrender tables indicate whether you should surrender your hand or play it.

They are used in the same way as the basic strategy tables. You will either find an empty cell or a number.

If the cell is empty, just follow the basic strategy. If the cell has a number in it, it means that you might have to deviate from the basic strategy and surrender.

The rule is lot more simple than with the deviation index table, just surrender if the count is superior or equal to the surrender index, apply basic strategy if the count is inferior.

An example would be with High-Low count, you hold 15 against a dealer's 9, the count is +4. The surrender index for this case id +2 therefore you should surrender. Don't even look to what the basic strategy says, just surrender.

What are balanced and unbalanced systems ? |
Back |

Counting systems fall into two categories, the balanced ones and the unbalanced ones.

- Unbalanced systems keep a running count and base their decisions on it alone. They usually start their count with a very negative value (around -20).

- Balanced systems also keep a running count but before taking any decision, they require that you convert this running count into a true count.

The true count is the running count divided by the number of decks remaining in the shoe. The True count is therefore positive if there are more high cards and negative if there are more low card in remaining in proportion in the deck. All the decisions are based on the True count.

On the side of the unbalanced systems, they are easier to use because you don't have to convert to the true count for every decision. And they are as effective as the balanced ones.

On the side of the balanced systems, you don't have to count very negative values, and they are easier to adapt to more advanced strategies. With some training it is not difficult to calculate the true count. They also do better than unbalanced ones against single deck.

Which system you choose is a matter of taste, the more comfortable you are with it, the less errors you will make.

What is a betting spread ? |
Back |

When counting cards you try to identify these periods when you have an advantage over the bank so you can bet bigger. If you flat bet (betting always the same amount) you can not take any advantage of it and it is totally pointless to count cards to start with.

The essence of card counting is to bet bigger when you have the advantage, but how bigger should you bet when you have 0.5% or 2% ?

There is a mathematical formula to calculate the exact amount you should bet in accordance to your bankroll and the advantage you have on the bet. This formula is the Kelly criterion.

The betting spread tells you how much you should bet for every count. It is system dependent as the different counts mean different advantages for each system.

For High-low a betting spread example would be

Bet 1 unit when counts <= 0

Bet 2 units when counts = +1

Bet 4 units when counts = +2

Bet 8 units when counts = +3

Bet 16 units when counts >= +4

It should be noted that for such a betting spread, you should have a bankroll of

High-low ? |
Back |

High-Low is a very famous balanced card counting system used by the MIT blackjack teams.

The card value tags are as follow :

Aces and Tens : -1

9, 8, 7 : 0

6, 5, 4, 3, 2 : +1

The reference book on the subject is Stanford Wong's Professional Blackjack.

KO ? |
Back |

KO is a very famous unbalanced card counting system. It stands for "Knock-Out"

The card value tags are as follow :

Aces and Tens : -1

9, 8 : 0

7, 6, 5, 4, 3, 2 : +1

The reference book on the subject is Olaf Vancura and Ken Fuchs's Knock-Out Blackjack: The Easiest Card-Counting System Ever Devised (Gambling Theories Methods).

reKO ? |
Back |

reKO is a more recent unbalanced card counting system. It is in fact a simplified version of (the already simple) KO system. It stands for "really (ridiculously) easy KO"

The card value tags are as follow :

Aces and Tens : -1

9, 8 : 0

7, 6, 5, 4, 3, 2 : +1

The reference book on the subject is Norm Wattenberger's online book Modern Blackjack

What is penetration ? and why is it important ? |
Back |

The penetration is the percentage of cards which are dealt from the shoe.

If 3 decks are dealt out of a 6 decks shoe before the shoe is shuffled, the penetration is 50%.

If 5 decks are dealt out of a 6 decks shoe before the shoe is shuffled, the penetration is 83%.

To put it simply, the bigger the penetration, the more you will be in presence of high counts and therefore in high advantage situations.

The penetration is so important that a shoe with a 50% penetration is barely playable.

When looking for a blackjack table with the intention of counting cards (which should always be your intention) you should avoid these low penetration shoes and look for better ones, 75% or more is highly recommended.

Should I play 1 or more hands? |
Back |

Let's cut short on this one, always play 2 hands.

As the Blackjack in color's graph shows it, the best is to always play 2 hands.

How do rules impact my advantage ? |
Back |

The rules of the game changes the edge of the bank. That is the edge for a player not counting the card, it also offsets the advantage a card counter will have. As an example, if a card counter can expect an overall 2% advantage over a break even game, it will only have a 1.5% advantage over a game presenting a -0.5% bank edge.

"Blackjack forum online" provides a list of rules and their impact.

All the given percentage are relative to a game with 1 decks, dealer stands on soft 17 (S17), player can double any two cards (DOA), player may double after split (DAS). This game being about break even, house edge = 0%

For example, let's take the following set of rules :

6 decks (-0.54%)

dealer has a hole card (+0%)

dealer stands on 17 (+0%)

double after split allowed (+0%)

late surrender (+0.08%)

This game would give a 0.46% edge to the bank. This is the typical edge you will find.