To Slot or Not to Slot? Chris Bray [email protected].
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Transcript of To Slot or Not to Slot? Chris Bray [email protected].
To Slot or Not to Slot?
Chris [email protected]
Definition
To slot is to expose a blot to an immediate direct shot with the objective of making a key point on the board.
Contents
General Principles The Opening The Middle Game The End Game
General Principles
Reasons for Slotting
To make a point that would be difficult to make ‘naturally’
To unstack heavy points To utilise sparse resources
effectively To reduce a game to a one-roll
proposition
Magriel’s Principles - Tactical
Do you have an advanced anchor? Having an advanced anchor enables you to play boldly.
How strong is your opponent’s home board? The stronger your opponent’s home board, the more conservatively you must play.
How strong is your home board (especially compared to your opponent’s)? If you have more home board points than your opponent, you tend to play boldly; with fewer points closed, more conservatively.
Does your opponent have blots in his home board? If your opponent has blots in his home board, you can afford to take more chances because of possible return shots.
Magriel’s Principles - Strategic
How many checkers do you have back? The more checkers you have back, the more chances you can take. With no checkers back, or only one checker back, you must play conservatively.
How many checkers does your opponent have back? When you opponent has no checkers back or only one checker back, you want to play provocatively to force an exchange of hits.
Other Key General Principles
Put your checkers where you want them
When in doubt, hit Prime an anchor; attack a blot When ahead in the race, race
The Opening
The Opening Roll – Black to Play 21, 41 or 51
Correct Play: Your choice!
Commentary
In the opening the bots will tell you there is always a best move but it is largely a question of style and what you feel comfortable with so play whatever you prefer.
For the record the bots’ preferences are to slot with 21 and split with 41 or 51.
Certain match scores will dictate whether to slot or split. When trailing you should prefer to slot and when leading to split.
The First Response
Correct Play: 13/9, 6/5
Commentary
Once the opening roll has been made you don’t have so much choice. There is nearly always a ‘best move’ in response.
When you opponent has brought down builders it is nearly always correct to slot with 21, 41 and 51 in response.
The reasons are: It duplicates some your opponent’s numbers It unstacks a heavy point Your opponent now has more checkers in ‘the zone’ so if you split a blitz
attack by your opponent becomes a possibility The equity differences are relatively small but big enough that you
should learn to slot in these situations.
And slightly later …..
Correct Play: bar/21, 6/5
Commentary
Here black is further behind in the race. Reject bar/24, 13/9 – an awful move that does virtually nothing to
improve your position The four is played bar/21 The one can be played 6/5 or 24/23 As in the previous position, 6/5 is the correct play
It duplicates some your opponent’s numbers It unstacks a heavy point The anchor on the 24-pt protects against a blitz
Bar/21, 24/23 is a common misplay in this type of position – learn to avoid it.
Opening Summary
Opening roll slot is optional (except in certain match play situations)
The response to the opening roll is not optional
When behind in the race early on slotting becomes more attractive
The Middle Game
Back in the 1970’s
Correct Play: 24/21, 24/23
Commentary
This and the next position are from from Barclay Cooke’s ‘Paradoxes and Probabilities’. Of the 168 problems in he book, 44 of them have solutions that are blunders!
In the 1970’s pure play was the order of the day! The trick here is to find the ‘Cooke’ move Cooke suggested 13/10, 6/5 - a move that does nothing to meet the
demands of the position! The front checkers are well positioned – time to get the back men
going with 24/21, 24/23 while white has only eight checkers in the zone and a disjointed position.
Back in the 1970’s (2)
Correct Play: 8/2*/1
Commentary
Here Cooke’s solution is even worse – 13/7, 5/4. Purity for purity’s sake! This is a huge equity error
We have learnt that once you start the ace-point you should quite often make it.
Here we have a lone back blot and remember – attack a blot. The obvious and correct play is 8/2*/1
Key Points to Consider Check Magriel’s Criteria How strong is your opponent’s home
board Life after death? How is the race? Is your opponent on the bar? How many back checkers does your
opponent have? Where is the cube? Gammon risk?
Simple Start – Slot, Split or Smooth?
Correct Play: 6/5
Commentary
The race is equal You opponent has the slightly better home board and ten checkers in
the zone. None of the basic criteria suggest slotting. You have a good position that can develop naturally Splitting allows a blitz attack and doesn’t gain enough in return The simple 6/5 is best – awaiting developments
Basic Question – Split or Slot?
Correct Play: 13/8, 6/5
Commentary
The five is obvious – 13/8. Then slot or split. Normally priming a blot is not the obvious plan but here 6/5 threatens
to create a five-point prime and if not hit give black a strong position. On the other side of the board once more white has 10 men in the
zone and a disjointed position. He would love black to split and give him the chance of a blitz
Once you study 13/8, 6/5 the play looks obvious but that doesn’t mean it’s easy to find over the board.
Is now the time?
Correct Play: 8/2, 8/7
Commentary
One could try a Cookesque 13/7, 6/5 but that would be a blunder. 7/1, 6/5 is a better slot However none of the basic criteria suggest slotting here. The race and positions are equal and there is no huge gain from
slotting. Time for a quiet waiting play 8/2, 8/7 Not the dreadful 21/14 (duplicating 2’s) as played in the game from
which this position was taken. White rolled 54 and played 13/4*. Black fanned and had to pass white’s double!
… or now?
Correct Play: 13/7, 13/8
Commentary
Here everything cries out for the slot 13/7, 13/8 Black has the better home board. If the slotted point is made black will have a very strong position If white hits, black could end up blitzing him because of all the return shots
and exposed blots (white may not hit with some of his ‘hitting’ numbers (e.g. 51) for precisely this reason)
White has blitzing potential (this is a recurring theme) The building play 13/8, 10/4 does not meet the demand of the position
Slightly more difficult
Correct Play: 15/11, 6/5
Commentary
Again all the criteria cry out for a slot: Black needs the 5-pt He is unlikely to make it naturally He is behind in the race He has an anchor Making the 5-pt could lead to a powerful double
The correct play is 15/11, 6/5 Any other move is a blunder or worse 13/9, 6/5 is also a big error! 15/11 provides more covers but I’m still
surprised at the equity difference. Note: The new bot ExtremeGammon prefers 15/11, 8/7 which opens
up a whole new debate
… and more difficult again
Correct Play: 13/9, 24/23
Commentary
This one is slightly surprising as it intuitively looks right to slot with 8/7 However, notice some key points:
The race is close There is no real duplication of white’s numbers While black builds his prime white will be counter-priming
Black does better by splitting 24/23 and attacking white’s blots. The plan may backfire and white run a successful blitz but black’s front position (his 5-pt) will protect him to a certain extent.
It is not a blunder to play 8/7 but it is an error. This is a difficult problem and many would get it wrong over the board. Note that the ‘do nothing’ play with the one – 6/5 – is the wrong idea.
Black should take action on one side of the board or the other
And really difficult!
Correct Play: 23/18, 15/14!!
Commentary
Fantastically difficult position from the 2009 World Championship Final!
The bots have taught us that when your opponent is on the bar you can take a lot of risks with slotting, especially when you have a five-point home board.
Any move other than 23/18, 15/14 is big mistake! Credit to Lars Trabolt for finding the play under the extreme pressure
of a WC final. Sadly his play was not rewarded with a win! Key point – when your opponent is on the bar is the time to take risks This position is a graphic demonstration of that principle
Piano or Forte?
Correct Play: 14/5
Commentary
This is an example of turning the game into a one roll proposition Black is crying out for his 5-pt – without it he can’t win the game Black must play 14/5. If white doesn’t hit he must drop black’s redouble next turn By slotting black makes himself a big favourite. Any other play leaves him with a lot of work to do.
Piano or Forte (2)?
Correct Play: 21/16, 11/10 or 21/15
Commentary
This one is not so clear The race is closer If black slots and gets hit he could lose a gammon He can get good outfield coverage with either 21/16 or 21/15, 11/10
(note he must ensure he gets hit with white’s 55) When good outfield coverage is possible it is often the right play and
here black must balance aggression against the gammon risk. Coverage wins and one of the quiet plays is correct.
Pick and Pass or Not?
Correct Play: 5/3*/2
Commentary
At first glance 5/3*, 11/10 looks obvious but White has a four-point board so when black is hit he will lose a lot of
gammons The race is relatively close Black is approaching a redouble and should not jeopardise that cube turn His checkers are well distributed anyway and the immediate capture of his
3-pt is not essential to winning the game The quiet play: 5/3*/2 is correct by quite some margin
Desperation Stakes?
Correct Play: 8/4, 24/23
Commentary
Here black is losing and losing badly Whatever he does he will lose a lot of gammons It will take a miracle to save him To do that he will need his 4-pt as soon as possible To do that he must slot it now with the hope of making it next turn 8/4, 24/23 is the only viable play!
The End Game
Considerations
How many checkers off? How strong are the home boards? Strength of outfield coverage? Which point requires slotting? Direct cover or not? (rule of thumb is to
have one direct cover before slotting) Where is the cube? How many men on the bar? (never slot
against two on the bar)
Open 6-pt
Correct Play: 14/6
Commentary
The 6-pt is often slotted. Lower points less frequently and the 2-pt and 1-pt are virtually never slotted.
The reason is that whenever your opponent enters on the 6-pt he also escapes – that is not true of the lower points.
Here there is an urgency to make the 6-pt in order to win the game Black already has two checkers out of play 14/6 is both thematic and correct.
Open 5-pt
Correct Play: 20/14, 13/11
Commentary
Just one point difference but now the slot is wrong! Making the point 6 away from the open point is a recurring theme in
positions like this 20/14, 13/11 provides excellent coverage without the risk of slotting White’s 3-pt board still ensures that black loses some gammons when
he is hit. It’s these gammon losses that swing the solution to 20/14, 13/11
Open 5-pt (2)
Correct Play: 13/5
Commentary
Now the situation is more urgent and white has a weaker home board. It’s surprising how weak the opponent’s home board has to be
(normally only two points) before you start taking liberties with slots and trap plays.
This (just) swings the answer to 13/5 but that play and 20/14, 13/11 are nearly equal in equity.
Note: Once again, ExtremeGammon disagrees and prefers 20/14, 13/11.
As Jeremy Bagai says in ‘Classic Backgammon Revisited’: “The pendulum of style continues to swing throughout the modern era, but the arc gets shorter as progress is made.” Maybe, but there’s still some interesting material to be found within that arc!
Open 5-pt (3)
Correct Play: 11/5*/4
Commentary
Another situation where black is closing in on a redouble. Now leaving the points slotted is overkill and when things go wrong
they go badly wrong and black can easily lose a gammon. White’s four-point board should set alarm bells ringing Simply best 11/5*/4 Black remains with excellent outfield coverage even if white enters.
Slot or Coverage?
The lower the point the less likely (or necessary) the slot.
Check for other significant factors Where is the cube?
The Right Conditions?
Correct Play: 21/19, 3/2
Commentary
These are the ideal conditions for slotting a lower point: White has only a two-point board White has an exposed blot in his home board Black will need his 3-pt to win the game Black can’t win with the cube so needs to play aggressively
All the criteria point towards the slot being correct The 2 can be played 14/12 or 21/19 as the two plays are equal
And finally ……….
Correct Play: 9/6
Commentary
The most famous slotting question in World Championship history. Should Joe Dwek (black) have slotted with this 21 against Lee Genud? Yes he should by playing 9/6. He doesn’t have a direct cover but the two blots on the 14- and 15pts
give him the equivalent of a direct cover and he must have the 6-pt to win the game.
Genud fanned and then Dwek slotted next turn but Genud entered with 65 hitting two blots and won easily from there.
Remember – two indirect cover numbers are often approximately equal to one direct cover number
The Play’s the Thing …….