return to indexSince we can't tell what is going to be rolled, we try to choose our playsso as to maximize the number of good rolls for our side and minimize thenumber of good rolls for the opponent. The latter can often be accomplishedby duplication. If a number is of use for the opponent in two places, thenhe can't do everything he wants to do unless he is fortunate enough to rolldoubles.
Let's look at a simple example:
| 155 156 | White money game Blue |
Blue would like to make his four point, but it isn't worth the risk ofslotting it. This is a mutual holding game with a close race, andBlue loses a lot of ground if White hits. The cost of this is more thanthe gain from making the four point. Blue should simply play 13/6 andawait developments.
However, change the position to:
| 147 156 | White money game Blue |
This is a different story. White needs aces very badly on his side of theboard to cover the blot on the five point. Here, Blue should slot with13/10, 8/4. White can Hit with an ace; in fact he probably will choose toso in preference to making his five point since the gain in the race isvery important and Blue might not hit back. However, White doesn't gainall that much from the hit, since using the ace to make his five pointwould have been a big improvement also. Of course if White doesn't rollan ace, Blue will be happy he slotted the four point because he can usethat point and will be a big favorite to cover it next roll.
The key to this type if duplication is that the opponent must need theduplicated number very badly in two places. If he only needs itmoderately in one place while it would be of huge value for him elsewhere,then the duplication isn't so valuable.
| 148 157 | White money game Blue |
I have seen players play 13/9, 4/3 in this type of position, justifyingtheir play by saying that they were duplicating White's fours. It is truethat White can use fours on both sides of the board, but the value ofthese fours is quite different. It would be convenient for White to makehis bar point with a four, but that is far from vital. White gainsa ton if he hits the shot, sending a third checker back while gainingin the race and escaping one of his back checkers. In addition, makingthe nine point isn't vital for Blue. Blue should simply play 13/8 andawait developments. This sort of slotting play is duplication forduplication's sake.
When the opponent is on the bar, there is often good opportunity to makeuse of duplication. If your opponent rolls anything with a six he willneed to enter with the other number and then play a six, so you don't wantto leave him good return sixes. Similarly, if he rolls something withan ace he would usually prefer to enter with the higher number ratherthan the ace. By making the middle numbers be his otherwise good numbers,you effectively duplicate his good numbes.
| 159 163 | White money game Blue |
Blue would like to anchor on White's bar point, and this is a good timeto continue to develop while White is on the bar. Despite this,Blue is better off playing 23/18*, 18/16 instead of 23/18*, 13/11.The key is the duplication. Blue doesn't want to give White good aces andsixes. After 23/18*, 18/16 White can't hit with 6-2 and 6-4, and if Whiterolls 1-2 or 1-4 he can hit but he winds up with three checkers on Blue'sace point. As an added bonus for B/18*, 18/16, the outfield checker issix pips away from the blot on Blue's ten point, so if White rolls a 6-4to hit that blot Blue will have a return six all ready.
The most obvious use of duplication comes when you are forced to leavemultiple shots. If you can position your checkers so your opponenthas the same number to hit in both places, you have cut down on hisgood rolls.
| 109 65 | White money game Blue |
Blue must play 16/11, 5/4, duplicating White's fours. Getting hit is fatal,and this gives White fewer hitting rolls than 16/10 or 16/15, 16/11. Thelatter two plays give White direct fours and threes to hit with, while16/11, 5/4 leaves White only direct fours plus a few indirect shots. Thisuse of duplication is very valuable when safety is the main criterion forthe play as it is here. Usually it isn't even necessary to count the actualshot numbers. Simply let duplication do the work for you.
Duplication can come in very handy in priming battles, where a player needsa specific number to leap or get to the edge of a prime. In this sort ofposition, proper use of duplication may cut down his good numbers.
| 114 106 | White money game Blue |
Blue could play 21/14, which would leave fewer shots and get closer tohome. However, this doesn't take proper advantage of duplication.White has very good sixes anyway. If White can spring his back checker,the race is close enough so he is a serious contender. The proper playis 21/15, 7/6, duplicating White's sixes. Now White must roll a six tostay in the game. If Blue plays 21/14, White is in the game if he rollseither a five or a six.
It is very easy to overdo the duplication concept. For example, makea small change in this last example:
| 146 106 | White money game Blue |
This time Blue should play 21/14. It is true that White can use a sixto leap a back checker, but this doesn't help him all that much. Blue shouldsimply leave fewer shots and get closer to home.
There is another interesting feature to this position. One might think itcould be right to hang back on the 15 point, since that doesn't giveWhite the hit and leap 6-5 number which would be very helpful to White.This is conpensated for by the fact that White might roll boxes. If Blueis on the 15 point and White rolls boxes, White becomes an instant favorite.
The above is an example of how duplication can blow up in ones face ifthe opponent rolls doubles of the number which has been duplicated. We haveall seen this happen, and when it does we just say: See, duplication strikesagain. However, when it is the only thing which can really go wrong, onechould be concerned about those devestating doubles when duplicatingthe enemy's numbers.
| 135 103 | White money game Blue |
It might seem instinctive to play 22/13, which minimizes shot numbers,duplicates White's aces, gets closer to home, and saves pips for thepriming battle in case White hits. Despite all these factors, Blue shouldplay 22/16, 7/4. The reason is entirely because of the threat of 1-1.If Blue plays 22-13, 1-1 is such a huge number for White -- hitting,making the five point, and splitting to the edge of Blue's prime.This would give White a real chance to win the game frontwards.If Blue plays 22/16, 7/4 and White hits, Blue is still going to remaina substantial favorite
Combination numbers can be duplicated just the same as single numbers.The idea is exactly the same -- minimize the number of good rolls for youropponent.
| 171 117 | White money game Blue |
It looks natural to play 12/11, 12/6. Moving the blot to the 11 point both reduces White's shotnumbers from six (5-4, 6-3, 6-5) to five (6-4, 6-2, 4-4), as well as getscloser to Home so the checker is more likely to be able to get safenext turn. A look at the other side of the board shows that this is thewrong play. 6-5 and 6-3 are already great rolls for White, since theymake his five point. 6-4, 6-2, and 4-4 are nothing special on White'sside of the board. Therefore, it is correct to stay back on the 12 pointand play 12/5. This play gives White fewer good numbers, since someof the hits are duplicated with making the five point. The bots arevery good at picking up on this sort of duplication, with their uncannyability to look ahead at all the possible upcoming dice rolls andevaluate them in an instant. Quite often I have been surprised by abot recommendation until I looked closer and saw that there was aduplication factor involved which I hadn't seen.
One must be careful using duplication. It is important not to fall intothe trap of duplicating for duplication's sake, creating good rolls forthe opponent when it is not necessary. It is also vital to stick with thelogical themes for the position. For example:
| 163 152 | White money game Blue |
A player could choose to play 13/7, arguing that White has several goodsixes anyway so his sixes are duplicated. That argument might be soundin other positions, but it doesn't hold up here. Blue has the racinglead and the stronger inner board. He loses that racing lead if Whitehits, and White will be on his way toward escaping a back checker. Inaddition, Blue's racing lead translates into favorable timing for White.If the timing remains the way it is, White will be the favorite in apriming battle. Blue's focus should be on getting his back checkersin motion before White is able to build up a strong board, not on slottingthe offensive bar point. 24/23, 13/8 is the play which is thematic to theposition. If it were White who was ahead in the race then the slotwould have a lot going for it, but in this position the split is theproper thematic play.