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January 21, 2012

Opening Reply Project

The opening reply project was something I did on my previous blog and I want to revisit the subject.  Last time around, I tried to memorize all the reply rolls for money, grouping reponses by reply roll.  Meaning, I would isolate and study how to play 54 against all opening rolls.

This time I want to try and do it the other way around.  I will look at each opening roll, and examine how to play all replies to that roll.  For example, I might look at 21$ (slot) and study how to play all rolls when facing this position.  This was recommended by Stick.

Additionally, I will try to deepen my knowledge a bit, by noting when alternative moves are close or are mistakes and if so, by how much.  I should say I will attempt to digest this information - who knows how things will really go?

Here are general principles regarding the opening reply rolls.  I call this "Bill's Guide to Opening Replies."

Wide variety of sources for this project including:

1.      Tom Keith excellent article: (

2.      Nactated replies compiled by Nack Ballard, current as of September 2009 from Stick’s website.  (one-page chart available via Tim Chow website

3.      My posts to Bill Blogs Backgammon, no longer available online.

4.      Stick Rice’s excellent Gammon Village article “Rules of Opening Play.” (** subscription required)

5.      David Rockwell’s article on slotting or splitting (from Phil Simborg website – no longer available online

6.      Kit Woolsey article on hitting from midpoint (from Phil Simborg website – no longer available online

7.      Zeman Milan, who complied my blog postings, added Diagrams as well as some of his own notes

8.      Double 3 chart and notes from BGO poster “taper mike.” (

Rules of Thumb

The first eight rules come from Tom Keith. I have added a few more.

1.      Hit an enemy blot on the opponent's side of the board.

2.      Knock an opponent's blot off your five-point or four-point.

3.      When you can't hit, then make a point in the usual way with these rolls: (31P, 42P, 53P, 61P)

4.      Hitting two blots is often good.

5.      Mirror your opponent's play.

6.      If the opponent makes his five-point, split your back checkers to try for an advanced anchor.

7.      If opponent splits his back checkers, be careful about leaving indirect shots.

8.      Be careful about coming under the gun.

9.      Slot with 21$, 41$, and 51$ unless your opponent has split his back checkers or has made an inner board point (Rockwell principle

10.  When opponent runs to the outfield, hit if you can.

11.  When your opponent slots and you miss, counterslotting is often correct. (Robertie)

12.  When opponent splits to the bar and you hit.

a.       if you hit with the six, split with the other half of the roll (Woolsey Principle)

b.       if you hit with the ace, come down from the mid-point with the other half of the roll. (Woolsey Principle).

13.  Make a point with 6-4 if opponent splits to 4pt or 5pt and you miss

14.  Rockwell on Splitting:

a.       MOTIVATION to split is less with a fourth guy on the 8-point.

b.      MOTIVATION to split is more with a loose blot on the outfield.

c.       It is a great time to split when opponent is on the bar

15.  41 Tower (13/8) is only correct against 52S.

16.  32”Wild” (24/21, 6/4) is right against 62$, 51$ and 63S, 62S

Bill’s “Always Hit” List: Exceptions and Discussion

1.      Always hit blot in the opponent's home board.

a.       21$-11 is the only exception. 8/7(2), 6/5(2) is slightly better. Reason is opponent's good sixes. 

b.      51$-11 is also an exception per zmilan

2.      Always hit blot in opponent's outer board. (Exceptions: some doubles.)

a.       33's. Never waste three 3's to hit on opponent's 10 point.

b.      43D-44. Against 43D, 24/20(2), 13/9(2) is better.

c.       Note 64S-22 is the only time you hit in outer board with 22 (24/16*)!

3.      Always hit blot in your outer board.

a.       Exceptions: 31P is usually better than hitting but not always.)

                                                              i.      64S-31. hit

                                                            ii.      split 24/21, 8/7* trumps the 5-point. (Note the power of the 9-point builder)

4.      When opponent major splits (to your 5 or 4 point), it is usually right to hit loose. If you can't do something constructive (like doubles, a point-making roll, or a better hit), the best you have is to hit loose and try to prevent your opponent from anchoring.  So, hit loose on "non-constructive rolls" (not a double, not a point-making roll, not a better hit elsewhere).

a.       For example: 43Z-21. You hit with 6/4*, 24/23

b.      or 54S-62. You hit loose with 13/5*

5.      When opponent major splits to the 5 or 4 point, sometimes it is right to hit loose even if you have a point making roll.

a.       You refrain from making a point, and hit loose instead on certain 61 positions

                                                              i.      43S-61. Hit and split 24/18, 6/5* instead of making the bar.

                                                            ii.      43U-61. Attack 13/7, 6/5* instead of making the bar

b.      You refrain from making a point, and hit loose instead on certain 53 positions

                                                              i.      43U-53. Hit loose with 13/5* instead of making the 3-point

                                                            ii.      43S-53. Hit loose with 13/5* instead of making the 3-point

                                                          iii.      54S-53. Hit loose with 13/5* instead of making the 3-point

c.       Note: 43Z-64. Running 24/14 is better than hitting loose or making the 2-point (though I don't understand why)

6.      It is often right to hit loose even against the minor splits (to the 3 or 2 point). Again, this rule would only apply to "non-constructive" rolls (not doubles, not a point, not a better hit).

a.       Examples of hitting splits to the 3-point:

                                                              i.      32Z-64. 13/3* is all you got

                                                            ii.      52S-64. 13/3* is all you got

                                                          iii.      32Z-43. 13/9, 6/3*

                                                          iv.      52S-43. 13/9, 6/3*

                                                            v.      52S-21. 6/3* is actually slightly wrong, but I like it anyway.

                                                          vi.      32Z-21. 6/3* gotta tap that ass.

b.      Examples of hitting splits to the 2-point:

                                                              i.      21S-41. Hit two with 6/2*/1*

                                                            ii.      41S-41. Hit two with 6/2*/1*

                                                          iii.      51S-41. Hit two with 6/2*/1*

                                                          iv.      21S-43. Hit and split 24/21, 6/2*

                                                            v.      41S-43. Hit and split 24/21, 6/2*

                                                          vi.      51S-43. Hit and split 24/21, 6/2*

7.      Hitting loose on the ace as a tempo play. Only when you roll a bad 5 against 6X, or in case of 41S-54.

a.       62S-54. hit and split 24/20, 6/1*

b.      41S-54. also hit and split 24/20, 6/1* (special case of the powerful 9-point builder) However, note Dmitriy Obukhov’s latest rollout has S and X essentially tied (

Stick’s Opening Rules

1.      When your opponent splits with an opening 6X [62 63 64] and you reply with a hitting 1X [21 41 51] you should play the other number (the non ace) down from the midpoint.

a.       The two possible exceptions in all of these variations is after your opponent opens with a 64 and split 24/18 13/9 and you roll a 21 or a 41. According to the latest and most powerful rollouts after you hit with the ace the splitting plays are tied with the plays that come down from the midpoint.

2.      When your opponent splits with an opening 6X [62 63 64] and you reply with a hitting 6X [62 63 64] you should play the other number (the non six) by splitting the back checkers

3.      When your opponent makes an inner board point on the opening roll [31 42 53 64] and you respond with doublets that allow you to advance your anchor do so. This does not apply to double aces.

a.       With 31P or 42P opponent wants to prime you.  Advancing the anchor cuts down gammon losses while also stopping his game plan.

b.      With 53P or 64P opponent makes a deep point. Advancing the anchor transforms the point your opponent just made into dead checkers instead of a useful point.

4.      If your opponent makes a big split in your inner board on the opening roll [32 43 52 54] and you reply with a roll where you will hit loose from either your 8pt or 6pt, use the other die to play down from the midpoint if possible.

a.       i.e. "if you hit loose on the second roll play the other die down from the midpoint"

b.      Main reason is give yourself good sixes and to unstack the mid-point.

c.       Exceptions: (quoting from Stick) "There are a couple of exceptions to this rule but they both involve your opponent rolling a 6X. Also, as with the other exceptions, if you were to follow the rule the errors you would be making are small.

                                                              i.      One exception comes after your opponent opens with an opening 43 and plays the big split, 24/20 13/10, seen less and less nowadays. (rightfully so imnsho) Now you roll 61, what to do? I could refurbish a decent explanation or direct you to a post by Nack Ballard with comparison positions that already does an excellent job of it. Nack's post.

                                                            ii.      The other exception to the rule is after an opponent opens with a 32 and plays the big split, 24/21 13/11. You now toss 62, what to do? You of course hit loose with the deuce and then playing out to the 18pt or down to the 7pt are tied according to GNU and Snowie rollouts. "

5.      The only second roll where you hit in the outfield with double twos is after your opponent splits with an opening 64.

6.      You only hit twice in your inner board on the second roll if you rolled 41 and your opponent split with 21, 41, or 51

7.      After your opponent opens with a 31 or 42 you will be moving the back checkers with any non natural point making number.

a.        It should be noted that although 64 is a 'natural point making number' it should not be used to make the 2pt after an opening 31 (you should run 24/14)

b.      and after an opening 42 it is basically tied as to whether you should make the 2pt or run 24/14.

8.      If on the second roll your opponent rolls double 4s or double 5s and uses the entire roll to make an offensive point do not touch your back checkers on the third roll.

a.       Explanation. Splitting the back checkers in these type of positions is usually a blunder and sometimes even worse. Your opponent will have 10 men in the zone and a very awkward and stacked position. The last thing you want to do is give him the opportunity to unpile his stacks on your head. You are behind in the race, you want to prime him. His structure is also not well suited to a priming game where you are more likely to have a smoother position. This concept can carry over into the 4th and 5th roll as well.

9.      When in doubt on how to play an early 21, slot!

a.       Stick recommends slotting against 51S, 41S and 61P

10.  These positions aren't cubes

a.       Examples of premature blitz cubes.  They all involve an early split by your opponent, you rolling aces and then him dancing on your 2 point board. You have no additional men in the zone and while you do have the start of a 4 prime it just isn't enough. The error range on cubing here is from ~.025 - .060 depending on the exact position of your opponent's outfield checker.

                                                              i.      62S-11N-F-C?

                                                            ii.      54S-11N-F-C?