After two wins, Zsolt faced Maurits in the 3rd round of the 1st Brugge Backgammon Day. The match turned out to be an interesting encounter with a shockingly spectacular Crawford game. You can download the annotated match (*.xg).
Maurits (left) and Zsolt (right) exchange niceties before the match
With the score tied at 1-1, both players found themselves in an opening skirmish. In such games it is mostly correct to keep hitting – Thou shallt hit in the beginning – but at a certain moment it becomes correct to anchor up and cut your losses. When that moment has come is not easy to assess. Here is how the game went :
Game 3
Zsolt Tasnadi (Black) needs 6 Maurits Pino (White) needs 6
1. 32 : 24/21 13/11 32 : 13/10 6/4*
2. 43 : bar/21* 24/21 64 : bar/21 24/18
3. 53 : 8/3 6/3 31 : ?
3. —– 31 : 18/14*
Hitting catches up in the race of course. White is only down 4 pips after the hit. The alternative would be to anchor up on the 18-point and play 10/9 with a less volatile position as a result. This turns out to be a serious error here :
1. XG Roller+ 18/14* eq:-0,31
Player: 44,87% (G:9,61% B:0,37%)
Opponent: 55,13% (G:19,20% B:1,22%)
2. XG Roller+ 21/18 10/9 eq:-0,376 (-0,067)
Player: 42,62% (G:8,46% B:0,28%)
Opponent: 57,38% (G:18,47% B:0,62%)
So, the fact that Black has made the 3-point should not deter you from hitting, even though the hit leaves 4 blots.
4. 65 : bar/20 21/15* 32 : ?
Maurits sees himself faced with the same problem : he can keep hitting and leave 5 (!) blots against a stronger board, or he can anchor up. What would you do?
4. —– 32 : bar/23 13/10*
Hitting is still correct, but by a much smaller margin :
1. XG Roller++ Bar/23 13/10* eq:-0,434
Player: 42,65% (G:9,33% B:0,36%)
Opponent: 57,35% (G:22,47% B:1,84%)
2. XG Roller++ Bar/23 24/21 eq:-0,457 (-0,024)
Player: 40,63% (G:8,45% B:0,29%)
Opponent: 59,37% (G:18,95% B:0,78%)
Just to show how subtle changes can make hitting wrong, have a look at this variation :
How to play this 42?
The extra spare on the 8-point and the fact that you can make the golden anchor are sufficient to make hitting an error :
1. XG Roller++ Bar/23 24/20 eq:-0,395
Player: 41,59% (G:8,69% B:0,27%)
Opponent: 58,41% (G:17,48% B:0,65%)
2. XG Roller++ Bar/23 14/10* eq:-0,422 (-0,027)
Player: 42,47% (G:8,82% B:0,30%)
Opponent: 57,53% (G:20,55% B:1,39%)
5. 62 : bar/23 21/15* 51 : ?
Hit-or-not?
5. —– 51 : bar/20 21/20
Maurits intuitively knows that enough is enough. Time to wave the white flag and fight a defensive war :
1. XG Roller++ Bar/20 21/20 eq:-0,364
Player: 43,28% (G:9,44% B:0,33%)
Opponent: 56,72% (G:20,13% B:0,88%)
2. XG Roller++ Bar/20 6/5* eq:-0,429 (-0,065)
Player: 44,12% (G:9,64% B:0,39%)
Opponent: 55,88% (G:25,82% B:2,75%)
Still, circumstances may occur where hitting here may be a tactical option worth considering. A world-class player might keep hitting to complicate matters. And, should this position come up towards the end of a match, the trailer might rightfully hit here if his oppenent is in time trouble.
6. 32 : 23/20 13/11* 31 : bar/24 13/10*
7. 52 : ?
Hit or not?
Now it is Zsolt’s turn to ponder whether he should hit or not. This position is fundamentally different, however. Here, Black has a significant edge (58% winning chances), whereas in the previous positions, White was always a clear underdog (40-45% winning chances) no matter what he did. This points to a consolidating play : Black should come in on the 20-point and make his 11-point. It is not so difficult to see that the 11-point is very strong against the 20-point anchor. Moreover, White already has 5 men back, so hitting a 6th checker might lead to a complex triple-anchor backgame where each checker play might pose challenging problems. Also, hitting gives up the golden anchor, a decision one should not take lightly.
Not hitting here yields a simple holding game with a 41-pip race advantage, low volatility and easy checker play coming up. The fact that Zsolt made the wrong choice here is indicative of how the intuitive hit may lead one astray in certain positions.
Still, the error is far from monstrous. Forward mobility and flexibility are important in positions where O (= opponent) has established multiple anchors.
1. XG Roller++ Bar/20 13/11 eq:+0,397
Player: 57,73% (G:18,75% B:0,91%)
Opponent: 42,27% (G:8,37% B:0,27%)
2. XG Roller++ Bar/20 11/9 eq:+0,341 (-0,056)
Player: 56,38% (G:18,28% B:0,88%)
Opponent: 43,62% (G:8,55% B:0,28%)
3. XG Roller++ Bar/23 20/15* eq:+0,331 (-0,066)
Player: 54,68% (G:22,44% B:1,72%)
Opponent: 45,32% (G:9,85% B:0,41%)
7. —– 43 : bar/21 24/21
8. 62 : 15/9 11/9 63 : ?
How to play this 63?
Having established a 5-4 backgame structure, it seems natural to just eject one of the back men into the outfield. This is probably what I would have done. Maurits, however, decides to go for Black’s barpoint by simultaneously slotting it and hitting on his 5-point. An ingenious tactical find in a complex position!
1. XG Roller++ 24/18 8/5* eq:-0,281
Player: 46,58% (G:10,32% B:0,43%)
Opponent: 53,42% (G:23,40% B:0,84%)
2. XG Roller++ 24/15 eq:-0,304 (-0,023)
Player: 45,03% (G:9,65% B:0,37%)
Opponent: 54,97% (G:20,59% B:0,62%)
3. XG Roller++ 23/14 eq:-0,309 (-0,028)
Player: 45,10% (G:9,65% B:0,38%)
Opponent: 54,90% (G:21,01% B:0,70%)
The reader can follow the rest of this exciting game via the link provided above. Both players held their own amid all that complexity : Zsolt scored a 4,36 PR (World Class), but was still outplayed by Maurits who even outplayed the computer : – 0,68 PR (Wow!). Nicely done.
M
That was a very nice article, Michel! Unfortunately I played th ematch as a whole much less well than this game. In fact, Zsolt and I had an error rate just above 8.5. Zsolt wasn’t lucky this match as I won a very fortunate and, as Michel indicated, spectacular, Crawford game, followed by a blitz – one of those early 55s that leave a player on the bar forever (a doubled backgammon in fact, although I needed only 3 points at that stage).