the dorbel daily

Sunday 27 March 2011

Don't Hit Me!

A common feature of mistakes at all levels of the game comes when we fail to evaluate positions from the viewpoint of the opponent. At the lower levels, novice, beginner and intermediate, this often shows itself when the student doesn't double positions that he would pass from the other side! Another common manifestation of this is reluctance to hit loose when the thing that all of us dread is being put on the bar! Here's a fine example shown to me by Rick Janowski. What would you do with a 6-1 here?

It's 0-0 to 7 points and Red trails in the race 119 to 99 before the roll. The home boards are on the right today.
XG 3-ply likes to run, as did one famous Giant Top 10 player. You might also consider the quiet 9/3, 9/8 and there are various ways to hit loose of which 9/2* seems to be the best. The current world champion voted for hitting but admitted that over the board he would probably have played 22/15. Hard problem? Now think of it from White's point of view. Would you like to be hit or would you like to be left alone to play all your roll in peace? It seems to me that you don't want to be hit for sure, which would lead to 9/2* and that is massively correct.
The running play is a huge blunder, losing about 0.25ppg against hitting and even the quiet play is a blunder costing about 0.12. Phew! If your usual tactic in prime/prime battles is to leave your opponent to break his prime then hitting seems to be anti-thematic, but it's right more often than most people imagine.
Some points to note here. Rick pointed out to me that leaving the anchor gives White the game plan that best suits her position. She can't improve her prime but she can blitz and her made 1 and 2pts will suddenly become assets.
White is at the edge of Red's prime, escaping with most fives on her next turn or later on. Hitting her away from the edge of the prime is axiomatic.
Red trails in the race which points to hitting and hitting also clearly wins more gammons. The cube is also a factor. If White can get out her race lead is usually enough for a strong double, whereas after the hit, only 5-2 from the bar (and a Red lemon) is good enough to turn the cube.

At the end of a match with a student, I had another position where I could hit or play quietly. Here it is.

It's Double Match Point and I lead 104-130 in the race. I thought about the nice quiet play 9/3, but in the end decided on 9/5, 4/2*, even though gammons are worthless. After White hit back and I danced twice and White escaped and the match went quietly down the tubes of course I regretted the hit, but it is correct. Putting White on the roof prepares to make the 2pt, stops her making another point inboard on her next roll (except for 2-2 and 1-1, both great numbers anyway) and most importantly creates the time and space to break the anchor and run them round. If you leave White alone this turn you will only face the same problem later, by which time she may have made another point or two inboard and be much more of a threat. Hard to see? Put yourself in White's shoes, do you want to be hit? The answer has to be no, so always do what the enemy least wants and whack it!
Until the next time, enjoy the game!

Saturday 19 March 2011

What Did You Do In The War Daddy?

Let's have some fun today and look at three checker plays that I got wrong over the board. I'll put the three positions up and we'll treat them like a quiz, so take a minute or two for each if you need it and write your answers down. I find that it is a big help to set the position out on a real board. In each position Red is on roll and the home boards are on the left.

Position 1.

5 Point Match, Red 1, White 0, Pipcount Red 137, White 137, Red to play 6-1

Position 2.

5 Point Match, Red 1 White 0. Pipcount Red 111, White 127. White owns the cube.

Red to play 5-1.

Position 3.

5 Point Match, first game. Pipcount Red 154, White 149
Red to play 6-4.

OK, Let's take a look at them. Position 1 first.

Over the board I played 11/5, 6/5. I vacillate between avoiding risks that should be taken and taking risks that should be avoided and for some reason I went for the "safety first" play here. That's too small and a blunder and the best play is actually 8/2, 6/5. This makes a third point and diversifies Red's spares, preparing to attack next turn if possible. The blot left behind on the 11pt isn't much use there, but if it gets hit there's going to be a lot of return shots and Red will have the stronger board.
TIP: If you have to bury a checker on the 1pt or 2pt, it's usually best to make it as soon as you can. It turns an embarassing and useless blot into a small asset. I should have done that and looked around for the 1. 11/10 isn't very bad, but it's an error compared to 6/5. I hope you didn't vote for 20/13. Leaving the golden anchor in an even race just can't be right.

Now on to position 2.

Red has a big solid lead here, 22 pips after the roll, so I decided to play 8/2 and hope to point on the White blot later. I find these problems so hard, it's a choice of "Pay now or pay later" isn't it. Like position 1 I vacillate between the two, perhaps it's a confidence thing. When my results are going well I play very freely, but tend to tighten up when things haven't gone so smoothly. The best play is actually 6/1*, 2/1. The idea of this is to bring the White checker "under the gun" so that with the security of my golden anchor I can hit it freely and go for a close out. This is the best plan because that horrid stack on the 5pt is useless for point making but will work quite well for hitting and covering the 2pt later. Of course this plan gives White an immediate shot from the bar that will equalise the race, but Red has a high anchor and will get return shots of his own, lots of them. The hit play wins 58% to the quiet plays 57%, but the big bonus is the extra gammons, 20 rather than 15 and a doubled gammon will take Red neatly up to 5.
Is there a useful guideline that might indicate to us when to move to a blitz? Yes there is.
TIP. The best way to take advantage of a better home board is to get into a blot hitting contest.
Put White on the roof here and he has 9 dancing numbers, compared to Red's 4. That's enough to go for the blitz option, particularly with that 20pt anchor as insurance and particularly here where Red can't really hope to build a prime.

Position 3 might be the hardest of these.

I decided to make the five prime, 13/7, 11/7. A five prime is a big asset of course, but Red pays too high a price for it here. It leaves a shot, it abandons the valuable midpoint and it leaves three checkers, 20% of Red's army still trapped. What else can we do? 11/1 is safe, but creates nothing and reduces Red to 14 playable checkers. 22/16, 5/1 is a bit better, but still buries a checker. Best of all is 22/16, 11/7! This escapes one man fom the anchor and slots the bar neatly duplicating fours. How important is it to escape a man?
TIP. The most useless spare is the one on your anchor.
You can't afford to have three checkers on your anchor; that spare has to get into the game, the sooner the better and this is quite typical. Strong players routinely jump this man into the outfield in much more dangerous situations than this.
Basically this is a prime versus prime contest and having as many checkers to play with as possible is paramount. That checker has to come out, not to race but to take part in the battle. Think of it as a battlefield reserve battalion; throw it into the battle now and it might tip the balance. Troops in reserve don't win any fights.
Well I learned a few things looking closely at these mistakes, I hope you did too. Until the next time, enjoy the game!

Wednesday 9 March 2011

More California Dreaming

If you looked at the previous post, you will remember that we are looking at a player who won seven games to six but lost the match 9-7. We'll pick up the match at 2-2, with Red on roll in this position.

He trails in the race a little, 120-113, but he has some poweful attacking chances here. Would you double this? Unquestionably you should. Are you 100% certain that this is a take for White? No? Then turn the cube! Easy isn't it? The key to this position is not so much the number of wins and gammons that Red can expect from here (65% wins including 20 gammons according to Snowie), but the volatility. The time to double blitz positions is before they work, not afterwards and here Red is about to launch a powerful and gammonish attack with sixes, fours and threes. 5-4 escapes and Red's only very bad numbers are the non-hitting 5-5 (which is at least 20 pips for the race!) and 5-2. Sadly Red failed to double this juicy blitz and worse, failed to hit loose when he rolled 3-2. White breathed a sigh of relief and rolled 6-6, making two points and putting Red on the bar. Red fanned to leave this position with White on roll.

As White , would you double this? As Red, would you take? White leads 89-116, but he does have four blots, he has two high points open in his board and he still has one man trapped behind a broken five prime. White (me) went with the volatility, doubled and Red passed. Now this is interesting, because if Red owned this position, I swear that he wouldn't double, yet he passes! I was in good company cubing, as Snowie 3-ply will double this, but rollouts (Snowie and Gnu) show that this isn't yet a double and of course passing is awful. Don't think so? Play it 50 times owning the cube and you will be astonished how many different ways Red has to win, both when he enters quickly and later when White fails to escape. Don't forget that on average it takes White just over three rolls to roll a five and if he can't escape in four rolls his board has usually collapsed. These positions have an interesting feature that is often overlooked. Red will keep his block in position when he dances, but White has to keep moving when he can't escape. Cube ownership is huge too. Anytime Red can enter and White can't hit or escape, Red can redouble to 4. It's probably a take but it's no great bargain.
It can't be emphasised too often or too strongly; backgammon is a game of aggression and the most aggressive player is the winner more often than not. Ask any world class player which opponent he prefers, a cautious player who is timid with the cube or an aggressive player who turns the cube at the sniff of a gammon. You are only going to beat a better player if you get the luck, so make sure that when it comes your way you are winning more than one point.
Until the next time, enjoy the game!

Sunday 6 March 2011

California Dreaming

Usually in this blog I try to focus on my own mistakes. It's good for my own learning process and avoids exposing people to unwanted criticism. Occasionally though, I get permission to feature somebody else's errors and here are some from a regular opponent on Fibs. He's ranked at 1755 which will give you some idea of where he stands in the hierarchy.
His problems, like those of so many, revolve around cube use. His checker play is quite good, but he has the worst possible combination of cube errors. He doesn't double early enough, he cashes games that are too good to double and tragically, takes some passes. Our latest match lasted for 13 games, of which he won 7 but lost the match 9-7.
Here's where the points went missing.

Red is on roll, he trails 0-2 to 9 and he leads 108-118 in the race. Should he double? Unquestionably yes. There are two ways of arriving at this. The first will stand repeating yet again, it is Woolsey's Rule. It goes, "Look at the position from your opponent's point of view. if there is any doubt about the take, it must be a double". "Any doubt" is the key phrase here, it means that if you are not 100% certain that it is a take, it must be a double. Actually it is a take, but certainly if doubled here I wouldn't be 100% certain and I certainly didn't want to be cubed.

The second way to look at it is this, an acronym called PRAT. This stands for Position, Race and Threats. Traditionally an advantage in two of these areas is thought to be enough for double and take and an advantage in all three is double and pass. Actually this is a bit too crude and you need to refine this a little and ask yourself how big these advantages really are, but it will do for this position. Red's Position is a bit better as White still has a man behind a four prime, but this is mostly counter-balanced by the fact that White is at least at the edge of the prime and his own strong board will make hitting loose by Red a risky option. The Race favours Red but it isn't overwhelming; a ten pip lead in a 108 pip pure race would be a take. The Threats favour Red, threats being sequences that lose the market, e.g if Red hits and White dances, then White will no longer have a take. We can see here that all the doublets are excellent, as well as 4-3, 4-2 and 3-2, that's 12 numbers straight off. In addition all the above average rolls play safely and there are only a couple of lemons, 2-1 and 3-1. So all in all, strong double for Red, uncomfortable take for White.

This next one isn't quite so obvious, what's the correct cube action here?

Red trails 1-2 to 9, but leads in the race 108 to 132. Woolsey's Rule, are you sure that this is a take for White? If you said, "Yes I'm sure", then you are a bit wide of the mark as this is actually a pass! Positions where you are anchored on the 24 or 23pt and your opponent has escaped all his men and leads in the race are usually passes. Don't be misled by the fact that White holds the 16pt as well. It isn't going to bother Red much on the way home and those checkers aren't much use to White until they move round to complete his board. If you are doubtful about doubling this as Red (or passing as White), set up the position and play it out 50 times. You should find that White will win 23-24% of these, but 11-12 of his losses will be gammons and that's enough to make it a close pass.
Another way of looking at doubling decisions is to adopt the advice contained in Clausewitz's Rules of War; "Always do what your enemy least wants". As Red the last thing that he wants is to be doubled here isn't it? If you evaluate this rather conservatively and think that this might be a double and might not, then Clausewitz has advice for that too. "Faced with two courses of action that are approximately equal in strength, choose that which allows your enemy the opportunity to make a mistake". If you leave the cube in the middle, no chance of a mistake. If you double on the other hand, he may take when he should pass (as here) or pass when he should take. I might well have taken this.
Moreover, once you have doubled you can't then make another doubling error, whereas the enemy may make several. There are many players who hate to double you in with a 4 cube, actually the player playing Red here is one of them. You can double these players in very early indeed, because they don't get the vig associated with owning the cube! All of these guidelines point to being aggressive with the cube.
In my next post we'll look at some more positions from this highly instructive match and discuss the important concept of volatility, but in the meantime, enjoy the game!