Opening Rolls - Part 3

Split or Slot Rolls
21
Firstly let’s discount the beginner’s move 13/10. Whilst not unreasonable it is not as productive as the other two moves that we shall discuss. The opening is the time when we can take risks to strengthen our position and whilst 13/10 unstacks a heavy point and prepares to make new points it is not as dynamic as the other two moves, both of which do two good things.

The first move to consider is 13/11, 6/5. This unstacks the two heaviest points and slots the most important point on the board- your own 5-pt. If red doesn’t hit this blot (and he is not favourite to do so) then black is an overwhelming favourite to make the point on his next turn.

If red does hit the blot then the black blot on the 11-pt is well placed to return hit on the 5-pt next turn. This is because it is six points away from the blot and a 6 is the one number black can’t use to re-enter.

The alternative play is the split, 13/11, 24/23. The objective of the split is twofold. It makes it more dangerous for red to bring builders into his outer board and it gives black several good rolls next turn to make an advanced anchor, e.g. 32 played 24/21, 23/21.

The split is less risky than the slot and consequently the rewards are not as high. When the slot works you will own your 5-pt, a significant improvement. When the split shows a profit it is normally by way of an advance anchor or a hit in reds outer board. These are gains not be ignored but the 5-pt asset is the biggest gain you can make in the opening. For this reason the computer programs all recommend slotting as the best play and it is what I also recommend to my pupils.

41
So do we just apply the same arguments to 41 and come up with the same conclusions? Sadly backgammon is not that simple and we must look more deeply.

Again we shall first discount the beginner’s move 13/8 for much the same reasons we discarded 13/10 as a viable alternative for our 21 opening. Whilst it is completely safe and brings another useful builder to black’s 8-pt it just doesn’t do enough at a time when you should be taking risks to improve your position.

Now lets looks at the other two moves... Firstly the slot, 13/9, 6/5 and secondly the split, 13/9, 24/23. The general theories of slot vs. split apply to these moves just as they did to our 21 opener. However, there are some mathematical differences that make this a much closer call:

i) After the slot, red has 19 hitting numbers (as opposed to 15 after 21) because he now hits with 62 and 53 as well as all 4’s.
ii) Because black’s builder is on the 9-pt rather than the 11-pt he has more point making rolls next turn even without slotting so it is possible that slotting is an overkill.
iii)If the slotted blot is hit then black no longer has a builder the optimal 6 points away and the checker on the 9-pt is less effective for hitting back.

These may seem like small differences but small differences is what backgammon is all about and the computers would have us believe that these differences are enough to make the split 13/9, 24/23 the correct play with an opening 41.

I think they are probably right but that doesn’t take into account the opponent factor. Against a weak opponent I will always play 13/9, 6/5 seeking the complexity that I believe gives me the edge. Against an opponent of equal strength or a stronger opponent I will elect for 13/9, 24/23.

One final point on 41. There are some other alternatives such as 24/20, 24/23 and 24/20, 6/5. Over time these moves have been discounted from the list of serious contenders. The former because it doesn’t take the option of unstacking the overloaded mid-point and the latter because it is just too bold, as we shall see subsequently, splitting and slotting in the same move is rarely correct. 

51
And so what about 51? Again there are subtle differences. Let’s look at the two moves, starting with slot, 13/8, 6/5 and now the split, 13/8, 24/23

The problem with both moves is that the ‘5’ doesn’t really improve black’s position. He already has a spare builder on his 8-pt. Another checker there is only a marginal improvement at best. However, most 5’s play poorly in the opening and we have to play what the dice gods give us.  13/8 is really the only option.

The problem with the slot is that when red misses the shot at the blot, whilst still favourite to make the 5-pt, black only has a 2-1 chance to do so rather than being the overwhelming favourite after the 21 and 41 slot plays.

For this reason the computers again prefer the split play 13/8, 24/23, although it is close. As in the notes to the 41 play I always play the slot against weaker opponents and in this instance also against equal opponents. Only against a much stronger opponent do I play the split.

With 51 there is a third alternative that gained some popularity a few years ago but it is not often seen at the moment. I think, however, that it is worth considering. The move is 24/18.

The theory behind this play is similar to that for the 62 and 63 moves that we have already considered. It seeks to enable black to either make red’s bar-point next turn or to promote an advantageous (to black) sequence of hits on red’s bar-point. It also uses the 5 effectively which neither the slotting nor the splitting play do.

I think this move should be tried from time to time, not only for the shock factor, but because I think it is a genuine contender.

Summary
So there we have it. With 21 it is fairly clear that the technically best move is 13/11, 6/5 but don’t forget opponent and match score considerations. Equally clearly with 41 the technically correct move is 13/9, 24/23 because the slot here can be viewed as overkill. With 51 the jury is out and the slot and the split are very close with the computers just giving the edge to the split.

It should be noted that this is current opinion. The original version of Jellyfish preferred to split with 21 and it is only later versions that advocate the slot. Computer technology is constantly evolving and who knows what Snowie 5 or 6 or 7 might recommend!

The best way forward for any individual is to try each of these moves, learn what type of games develop from each, and learn what you are comfortable with. Never forget you are playing another human being and that may well be the determining factor.

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