# Backgammon rules question **URL:** \ **Category:** The Game Room\ **Created:** [March 17, 2020, 12:20am UTC](https://boards.straightdope.com/t/backgammon-rules-question/849616 "2020-03-17T00:20:30Z")\ **Posts on this page:** 16\ **Page:** 1
**Author:** ![Enderw24](https://avatars.discourse-cdn.com/v4/letter/e/ba9def/32.png) [@Enderw24](https://boards.straightdope.com/u/Enderw24)\ **Post date:** [March 17, 2020, 12:20am UTC](https://boards.straightdope.com/t/backgammon-rules-question/849616/1 "2020-03-17T00:20:30Z")
A player rolls a 6 and a 2. Suppose the game state is such that there’s currently no legal 6 moves to make. There are two potential 2 moves to make. One of them would continue to make any 6 move illegal. The other would allow a 6 move. Is there a requirement that both dice numbers be utilized if there’s any possibility to do so? In other words, forcing the 2 that would open up the 6. Or can a player choose to lock themselves out of their second move? ---
**Author:** ![penultima\_thule](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/penultima_thule/32/3833_2.png) [@penultima\_thule](https://boards.straightdope.com/u/penultima_thule)\ **Post date:** [March 17, 2020, 12:34am UTC](https://boards.straightdope.com/t/backgammon-rules-question/849616/2 "2020-03-17T00:34:10Z")
> [@](#): > > Is there a requirement that both dice numbers be utilized if there’s any possibility to do so? Yes. > **[F.G. Bradley's Pool Tables, Darts, Poker, Bar Stools & Game Tables](https://fgbradleys.com)** > > Featured Items Strategy Games The Vale of Eternity 0 out of 5 $37.99 View It! Add to wishlist Glassware, Glassware Final Touch Brainfreeze Skull Beer Mug > [@](#): > > A player must use both numbers of a roll if this is legally possible (or all four numbers of a double). When only one number can be played, the player must play that number. Or if either number can be played but not both, the player must play the larger one. When neither number can be used, the player loses his turn. ---
**Author:** ![Enderw24](https://avatars.discourse-cdn.com/v4/letter/e/ba9def/32.png) [@Enderw24](https://boards.straightdope.com/u/Enderw24)\ **Post date:** [March 17, 2020, 4:37am UTC](https://boards.straightdope.com/t/backgammon-rules-question/849616/3 "2020-03-17T04:37:31Z")
So this appears to answer it but there’s still wiggle room. A player must use both rolls when it’s legally possible it says. But at the start it wasn’t legally possible. It was only possible to play the smaller number. What I ended up doing was letting my daughter move the two where she wanted and thus keeping the 6 impossible. Otherwise she’d have had to open herself up where I could likely capture her piece next turn. ---
**Author:** ![Dead\_Cat](https://avatars.discourse-cdn.com/v4/letter/d/9fc29f/32.png) [@Dead\_Cat](https://boards.straightdope.com/u/Dead_Cat)\ **Post date:** [March 17, 2020, 9:16am UTC](https://boards.straightdope.com/t/backgammon-rules-question/849616/4 "2020-03-17T09:16:41Z")
> [@Enderw24](#): > > So this appears to answer it but there’s still wiggle room. A player must use both rolls when it’s legally possible it says. But at the start it wasn’t legally possible. It was only possible to play the smaller number. No wiggle room - you have to consider the whole roll. If it’s legally possible to play both numbers (even if the order you play them is forced), you must do so. It was kind of you to give your daughter the benefit of the doubt, as you weren’t sure. But if I were you, I’d go back and explain the definitive answer, in case it comes up again. It’s not uncommon in backgammon for it to be preferably to ‘pass’ rather than move if that were allowed, this is just a special case of that. ---
**Author:** ![glee](https://avatars.discourse-cdn.com/v4/letter/g/b5a626/32.png) [@glee](https://boards.straightdope.com/u/glee)\ **Post date:** [March 17, 2020, 9:50am UTC](https://boards.straightdope.com/t/backgammon-rules-question/849616/5 "2020-03-17T09:50:42Z")
> [@Dead\_Cat](#): > > It was kind of you to give your daughter the benefit of the doubt, as you weren’t sure. But if I were you, I’d go back and explain the definitive answer, in case it comes up again. It’s not uncommon in backgammon for it to be preferably to ‘pass’ rather than move if that were allowed, this is just a special case of that. As a chess coach, I agree that you should stick carefully to the rules of every game, even when playing beginners. I remember teaching chess to a group of 7-9 year olds in a school, when one of them said “The horse can’t move backwards!” After investigating, it turned our their uncle had given them some muddled lessons. I had to tread carefully, since you don’t want to: - embarrass the child - ‘show up’ an uncle (even if they are wrong.) ---
**Author:** ![Novelty\_Bobble](https://avatars.discourse-cdn.com/v4/letter/n/a3d4f5/32.png) [@Novelty\_Bobble](https://boards.straightdope.com/u/Novelty_Bobble)\ **Post date:** [March 17, 2020, 9:24pm UTC](https://boards.straightdope.com/t/backgammon-rules-question/849616/6 "2020-03-17T21:24:54Z")
I confess, I’m an infrequent player but under what circumstances could an initial move of 2 make a previously impossible move of 6, possible? I think I’m missing something obvious here. ---
**Author:** ![muldoonthief](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/muldoonthief/32/3188_2.png) [@muldoonthief](https://boards.straightdope.com/u/muldoonthief)\ **Post date:** [March 17, 2020, 9:32pm UTC](https://boards.straightdope.com/t/backgammon-rules-question/849616/7 "2020-03-17T21:32:22Z")
> [@penultima\_thule](#): > > Yes. > [F.G. Bradley's Pool Tables, Darts, Poker, Bar Stools & Game Tables](https://www.fgbradleys.com/rules/Backgammon_Rules.pdf) > > A player must use both numbers of a roll if this is legally possible (or all four numbers of a double). When only one number can be played, the player must play that number. Or if either number can be played but not both, the player must play the larger one. When neither number can be used, the player loses his turn. Huh. I knew the rule that you had to use the whole roll if possible, but I never knew (and neither did anyone I ever played) that if you could play either but not both that you had to play the larger. I assume that occurs pretty infrequently though. ---
**Author:** ![Calavera](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calavera/32/70_2.png) [@Calavera](https://boards.straightdope.com/u/Calavera)\ **Post date:** [March 17, 2020, 10:09pm UTC](https://boards.straightdope.com/t/backgammon-rules-question/849616/8 "2020-03-17T22:09:50Z")
> [@Novelty\_Bobble](#): > > I confess, I’m an infrequent player but under what circumstances could an initial move of 2 make a previously impossible move of 6, possible? I think I’m missing something obvious here. I’m no backgammon player but I assume counter A has a block 6 and 8 spaces away, counter B has a block 6 spaces away but not 8. You would prefer to move counter a 2 and pass, but cannot because the rule is you have to move counter B if that’s the only way to use them both. ---
**Author:** ![Novelty\_Bobble](https://avatars.discourse-cdn.com/v4/letter/n/a3d4f5/32.png) [@Novelty\_Bobble](https://boards.straightdope.com/u/Novelty_Bobble)\ **Post date:** [March 18, 2020, 8:09am UTC](https://boards.straightdope.com/t/backgammon-rules-question/849616/9 "2020-03-18T08:09:49Z")
> [@Calavera](#): > > I’m no backgammon player but I assume counter A has a block 6 and 8 spaces away, counter B has a block 6 spaces away but not 8. You would prefer to move counter a 2 and pass, but cannot because the rule is you have to move counter B if that’s the only way to use them both. Actually I see what I’ve done here, I was assuming from the OP that they are talking about moving one counter 2 moves so that it would open up a previously illegal 6 move for the other counter. I couldn’t see how that would happen (and still don’t think it could) but your explanation is indeed valid and it is the way I understand the game. Not bad wording on the OP’s part but bad reading on mine. ---
**Author:** ![Dead\_Cat](https://avatars.discourse-cdn.com/v4/letter/d/9fc29f/32.png) [@Dead\_Cat](https://boards.straightdope.com/u/Dead_Cat)\ **Post date:** [March 18, 2020, 11:05am UTC](https://boards.straightdope.com/t/backgammon-rules-question/849616/10 "2020-03-18T11:05:07Z")
> [@muldoonthief](#): > > Huh. I knew the rule that you had to use the whole roll if possible, but I never knew (and neither did anyone I ever played) that if you could play either but not both that you had to play the larger. I assume that occurs pretty infrequently though. Yes, unlike the situation in the OP, this is pretty rare. Here is a possible position where it could come up (Xs represent checkers of one colour, moving right to left, Os represent the other colour, moving left to right): ```auto X X X X X X X X X X X X X X X O 15 16 17 18 19 20 21 22 23 24 ``` In the diagram, assume O’s 14 other checkers are all on their 3-point or less (on the other side of the board, not shown), and they are to play a roll of 6-3. They can move the checker shown 3 spaces, or 6 spaces, but not both - so they must move 24-18, using the 6 only. Of course, in this particular situation that would be the best choice anyway, but the rules give no choice in the matter. Hope that makes sense. A very similar situation can be used to illustrate the OP: ```auto X X X X X X X X X X X X X X X O 15 16 17 18 19 20 21 22 23 24 ``` Again assuming all the other O checkers are on the 3-point or less (on the other side of the board, not shown), if O is to play a roll of 6-2 here, they must move the checker shown 24-22-16 (normally notated as just 24-16, but I am adding the intermediate step here to fully illustrate the point). They would not be allowed to move one of the O checkers from the 3-point to the 1-point (3-1), and then claim no 6 is playable. Though again, in this particular situation the latter would be a foolish thing to do even if allowed, whereas in the OP’s case this apparently wasn’t so. ---
**Author:** ![septimus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/septimus/32/410_2.png) [@septimus](https://boards.straightdope.com/u/septimus)\ **Post date:** [March 18, 2020, 1:05pm UTC](https://boards.straightdope.com/t/backgammon-rules-question/849616/11 "2020-03-18T13:05:54Z")
The same rule was discussed in a 2-years-ago thread: > [@Go](https://boards.straightdope.com/t/go/810762/16): > > There’s a possible ambiguity in the rule: > > - You must take your entire roll if possible.\* > > ```php > +13-14-15-16-17-18------19-20-21-22-23-24-+ > | O O | | O O O O O | > | | | O O O O O | > | | | | > | | | | > | | | | > | |BAR| | > | | | | > | | | | > | | | | > | | | X O | > | | | X X O O | > +12-11-10--9--8--7-------6--5--4--3--2--1-+ > > ``` > > If X rolls 3-1 in this position he is not allowed to play 6/5 and say “I have no 3.” He must find a way to play both 3 and 1 … and thereby leave three blots! > > HOWEVER, if he rolls 6-1 he is NOT required to play 6/0 5/4 and leave two blots. He is allowed to play safe with 6/5/0 — this is considered “taking the whole roll” even though a pip is wasted with the 6. (Some of the followuup was [in a separate thread](https://boards.straightdope.com/sdmb/showthread.php?p=20952623).) ---
**Author:** ![Novelty\_Bobble](https://avatars.discourse-cdn.com/v4/letter/n/a3d4f5/32.png) [@Novelty\_Bobble](https://boards.straightdope.com/u/Novelty_Bobble)\ **Post date:** [March 18, 2020, 1:17pm UTC](https://boards.straightdope.com/t/backgammon-rules-question/849616/12 "2020-03-18T13:17:23Z")
> [@septimus](#): > > The same rule was discussed in a 2-years-ago thread: > (Some of the followuup was [in a separate thread](https://boards.straightdope.com/sdmb/showthread.php?p=20952623).) Thanks for that septimus, I don’t think I’ve come up against that in real play and I’m not sure what I would have decided. Probably to use the move that uses the whole of the score but good to know that the alternative is valid in those circumstances. ---
**Author:** ![Enderw24](https://avatars.discourse-cdn.com/v4/letter/e/ba9def/32.png) [@Enderw24](https://boards.straightdope.com/u/Enderw24)\ **Post date:** [March 18, 2020, 8:14pm UTC](https://boards.straightdope.com/t/backgammon-rules-question/849616/13 "2020-03-18T20:14:59Z")
```php +13-14-15-16-17-18------19-20-21-22-23-24-+ | o O | | X X X X | | o O | | X X X | | O | | X X | | | | X | | | | x | | |BAR| | | | | | | | | o | | | | o O | | x X | | o O O | | x X | | O O o O | +12-11-10--9--8--7-------6--5--4--3--2--1-+ ``` I’m doing this on mobile so I’m trying my best, but here’s the board. My daughter is the X. As you can see there’s no current legal 6. There are multiple 2 moves available. If she chooses 19-21 there will still be no legal 6. But if she chooses 12-14 or 7-9 she can move a 6. I let her move the 19-21. But you’re all saying that’s not a proper move. I’ll know for next time. ---
**Author:** ![Dead\_Cat](https://avatars.discourse-cdn.com/v4/letter/d/9fc29f/32.png) [@Dead\_Cat](https://boards.straightdope.com/u/Dead_Cat)\ **Post date:** [March 19, 2020, 9:24am UTC](https://boards.straightdope.com/t/backgammon-rules-question/849616/14 "2020-03-19T09:24:06Z")
It’s not perfect, but that’s a remarkably good effort to produce an intelligible full board position from mobile - it took me ages to sort out my much more rudimentary diagrams, using a laptop! Having resolved the rules question, it’s an interesting position to analyse as to whether 7-15 or 12-20 is the best move. Without counting, my intuition is they both leave the same number of shots for O’s next role. So I think I’d play 12-20 - it starts the 5 point, and if the shot is missed it is quite likely X will be able to leave no blots next roll. The disadvantage is that it leaves the remaining 2 checkers on the 7 point out in the cold - but these may get a chance to hit any blots that O leaves in the outer boards. ---
**Author:** ![septimus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/septimus/32/410_2.png) [@septimus](https://boards.straightdope.com/u/septimus)\ **Post date:** [March 21, 2020, 7:57am UTC](https://boards.straightdope.com/t/backgammon-rules-question/849616/15 "2020-03-21T07:57:34Z")
How old is your daughter? I think there’s a fair chance she knew the rule but was taking advantage of Dad! Gnu Backgammon shows the chances for each move (though it has to be tricked slightly to consider the illegal move). 19/21 .504 .101 .001 .496 .123 .002 12/20 .432 .109 .002 .568 .182 .008 7/15 .379 .115 .002 .621 .262 .011 As **Dead Cat** implies, 12/20 wins 43.2% of games compared with 37.9% for 7/15. But your daughter’s move wins 50.4% of the time! ---
**Author:** ![Enderw24](https://avatars.discourse-cdn.com/v4/letter/e/ba9def/32.png) [@Enderw24](https://boards.straightdope.com/u/Enderw24)\ **Post date:** [March 23, 2020, 1:05am UTC](https://boards.straightdope.com/t/backgammon-rules-question/849616/16 "2020-03-23T01:05:58Z")
> [@septimus](#): > > How old is your daughter? I think there’s a fair chance she knew the rule but was taking advantage of Dad! In general? I totally wouldn’t put it past her to try something like that! Here? No, she’s 9 and I had just taught her Backgammon the week before. So I believe she was as clueless as I was.