The Duplication Strategy in Backgammon

Winning every game of backgammon is an unattainable goal, but winning more than you lose is definitely achievable, which can turn you into a consistent winner in the long run. Duplication and non-duplication are two crucial strategies that can aid you in achieving this goal. Interestingly, these strategies are often so subtle that even experienced backgammon players remain oblivious to them for years. As a result, they attribute their opponents’ wins to luck, without realizing the intricate secrets behind the moves chosen based on these principles.


Here’s a simplified illustration of the duplication strategy in action. In the given diagram, White has just rolled a 4:1. How should White play this roll?


The optimal move for White in this situation is to move their checker from point 13 to point 8. If Black rolls a 4, they will have to use it to re-enter their checker and will be unable to hit the White blot, which is exactly 4 spaces away. However, in the unlikely event that Black rolls a double 4 (4:4), White must accept that their opponent has gotten lucky. If White had left their blot on point 9, Black would have had two chances in 36 to re-enter and hit it with a roll of either 5:4 or 4:5. By moving the checker to point 8, Black can now only enter and hit with a roll of 4:4, reducing their chances of success by 50%. This is an example of how duplication can be used to significantly reduce the opponent’s chances of hitting a vulnerable checker.


The same principle of duplication applies when you are in a situation where you must expose two blots. The risks of having both blots hit simultaneously and the challenges of re-entry are significant, so it is crucial to minimize the risk as much as possible. Duplication can often be employed to address this problem. The diagram below provides an example of how duplication can be used in a scenario with two blots. In this particular case, White has just rolled a 5:3.

Since White cannot cover their blot on point 3, they play their roll of 5 by moving their checker from point 20 to point 15, and their roll of 3 by moving their checker from point 7 to point 4, as shown in the diagram. By doing so, Black can now only hit both blots with a roll of double 3 (3:3), which has a probability of 1 in 36. If White had left the blot on point 3 or moved it to point 17, there would have been a greater number of rolls that Black could use to hit both blots. Once again, the principle of duplication has effectively reduced the chances of both blots being hit to just 1 in 36.

In the given diagram, White has just rolled a 6:1 and is faced with a situation where they must expose three blots. Despite the risks involved, White decides to employ the duplication strategy in order to mitigate those risks. Duplication involves strategically placing checkers in such a way that the opponent’s chances of hitting vulnerable blots are minimized. In this case, White’s goal is to reduce the chances of all three of their exposed blots being hit simultaneously.


In this particular move, White has used the duplication strategy to minimize Black’s chances of hitting all three of White’s exposed blots simultaneously. White starts by hitting the Black blot on point 15 with their roll of 6, thus reducing the number of rolls that Black can use to hit multiple blots. Next, White moves their checker from point 4 to point 3, since they cannot cover that blot. By doing so, White once again creates a duplicated number, which limits Black’s options on their next turn. If Black rolls any 3, they will have to re-enter their checker and will not be able to hit either of the blots on points 4 or 15. While there is still a slim chance that Black could roll a double 3 (3:3) and win the game, this move effectively reduces the likelihood of that happening. By using the duplication strategy, White has significantly increased their chances of winning by minimizing the risk of losing multiple checkers on Black’s next turn.


In this scenario, White has thrown a 6:1 and has successfully used the 6 to move their last checker out of the Black home board. However, White still has one more roll to make with a single pip. The question is, how should White play their last roll of 1?

Without careful consideration, White may simply move their checker on point 5 to point 4, leaving their checker exposed to a potential hit by Black on their next turn. However, a better move would be to use the duplication strategy and move their checker from point 5 to point 4 while also moving the checker on point 2 to point 1. This creates a duplicated number, making it more difficult for Black to hit White’s blot on point 4 on their next turn.

By making use of the duplication strategy, White is able to reduce the risk of losing their checker on the next turn, thus increasing their chances of winning the game.


White can use the duplication strategy once again in diagram, where he has thrown a 6:1 in backgammon. To make the most of his roll, he uses the 6 to move his last man out of the Black home board. However, he must carefully consider how to play the 1.

In this situation, White leaves his man on 18 where it can only be hit by a 6 and plays the 1 to move his blot from 4 to 3. If Black chooses to hit the blot, he will have to use his 6 to do so, which means he will also have to extricate his last man from the White home board. Therefore, Black cannot risk leaving his man in White’s trap and must remove it with any 6.

By using the duplication strategy in this way, White has reduced the chances of his blot being hit by Black to just one roll of 6:6. If White had moved his blot to 17 with the 1, Black would have had multiple chances to hit it with any 5, as well as removing his man with any 6.


Develop the habit of searching for situations where duplication can give you an edge in backgammon. Whenever you have an opponent on the bar, take a moment to consider whether duplication can be of help before making your move. As shown in the diagram, White rolls 4:2, and his opponent can only re-enter with a 1 or 4. This means that the most secure positions to leave your blots are at a distance of 1 or 4 points away from the black men.


In this scenario, White has thrown a 4:2 and wants to use duplication to his advantage. He knows that his opponent must use any 1 or 4 to re-enter the game, so he moves one of his men from 20 to 14 where it can only be hit by a 1 or 4. The other blot, on point 20, can also only be hit by a 1. By doing this, White ensures that his blots are safe from being hit by numbers that are not required for re-entry, such as 6, 5, or 3, which can be used to hit blots. It is important to note that White did not move both men to 18 and 16, where they could have been hit by a 6, 5, or 3.



In the given scenario, preventing Black from escaping is crucial for White. If Black manages to escape, he will have a good chance of winning the game. After White throws 5:1, he hits Black’s piece on point 7 with the 5 and now needs to decide how to play the 1. To minimize the risk of losing his advantage, White must assume that Black will re-enter and hit the blot on point 2. In such a case, White will be forced to use any 5 for re-entry, leaving the spare man on point 7 unavailable for re-hitting the black blot. Therefore, in this situation, it is important for White to leave no other blots for Black to hit.


Therefore, White chooses to move his man from point 7 to point 6 instead of moving the blot on point 20 to point 19 to avoid duplication. By doing this, he ensures that he doesn’t waste the numbers 3 and 4, which could be used to hit Black again if needed. Since Black will most likely re-enter the game and hit the blot, White will be forced to use any 5 to re-enter, which means that the man on point 7 will not be available to hit Black again.


White’s objective is to close up his home board, but he faces a problem as he has just thrown 6:4 and cannot cover his blot. To overcome this, he must anticipate that Black will re-enter and hit the blot on his next turn. In this scenario, White will need any 5, 3 or 2 for re-entry. Thus, he must plan his moves carefully and position his men strategically so that they can re-hit the black blot with 6, 4 or 1.


White, after throwing 6:4, plays 8-2 with the 6 and 9-5 with the 4, positioning his men so that any roll of 1 or 4, which are not needed for re-entry, can be used to hit the black blot on the 1 point.


When playing backgammon, it’s important to make moves that anticipate future plays by your opponent. For example, if you leave a blot on the board, assume your opponent will re-enter and hit it. In a correct move, White plays 6:3, 5:1 to leave himself with options to re-hit the black blot with a 1, 4 or 6. However, in an incorrect move, White plays 9:3, 8:4, which limits his options for hitting the blot and could use up numbers needed for re-entry.

It’s easy for inexperienced players to miss the importance of planning ahead in backgammon. While the game involves dice rolls that can be unpredictable, it’s still important to think at least two turns ahead, considering your opponent’s potential moves as well as your own. By doing so, you can increase your chances of making successful plays and avoiding mistakes blamed on luck rather than skill.


In this scenario, White has just rolled a 3:2 and needs to consider two factors:

  1. Bringing up his builders to improve his chances of hitting any Black blot that may re-enter on 4.
  2. Escaping his last two men from the Black home board.

If White moves one man from point 13 to point 8 with his 3:2 roll, he will only be able to hit on 4 with a roll of 4. However, White cannot afford to use every 4 he rolls to remove his men from the Black home board. Thus, he must move his men in such a way that a hit is possible with a roll other than 4, in order to preserve his 4 rolls for escaping from the Black home board.


The right move for White is to move one man from 13 to 10 and the other from 13 to 11. This move allows White to use all 4s to move his men out of the black home board and any 6s to hit on 4. By avoiding duplication of a crucial move, he has not reduced his chances of escaping and hitting.

Duplication and non-duplication moves are useful in improving the odds of getting a favorable roll in the next turn. They tip the scales of probability in your favor and against your opponent’s.

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