To Slot or Not to Slot

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					To Slot or Not to Slot?

       Chris Bray
      chris.bray@btconnect.com
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 …….