Wednesday, November 07, 2007

Find the duplo-moves

Duplo-moves are the technique par excellence to gain wood.
There are 3 duplo-moves:
  • double attack
  • discovered attack
  • pin/skewer
If these duplo-moves are not around (and there is no trap), you cannot gain wood.
Ask yourself these questions:
  • Are there duplo-moves around?
  • Are the targets in place? If not, put them in place.
  • Are there defenders of the attacking square(s)? Remove the defenders.
Let's have a look at another problem of Glenn:

White to move.

  • Are there duplo-moves around? Yes, B or Q d5 double attack on R and K
  • Are the targets in place? Yes
  • Are there defenders of the attacking square(s)? Remove the defenders. Nxc6 followed by Nxd5 undermines the d5 square
If after 1.Nxc6 bxc6 2.Nxd5 the black king moves to h8:

  • Are there duplo-moves around? Yes, pin with Qa3 the black knight on d6.
  • Are the targets in place? No, play Nxe7
  • Are there defenders of the attacking square(s)? No.
I guess it's just a matter of doing a lot of problems, identifying the duplo-moves and creating narratives based upon them.


  1. So, in practice, for a potential counting position:
    1. Check for tactics,
    2. Do the counting thing,
    3. Check the subsequent and intermediate positions from counting for tactics.

    Is that about right?

    A finely honed feel for tactical opportunities and pattern recognition would help with steps 1 and 3.

  2. Glenn,
    duplo-moves before: a duplo move can attack two pieces that are sufficiently protected. The defender can only safe one of them. Overprotection secures the defender so that this isn't possible any longer.

    duplo-moves after: since the attacker is going to gain wood, he has the possibility to invest beforehand.
    Such investment overrules the simple counting method.

    duplo-moves during: you have to count defenders. Buth that only works as the defender defends. Due to a duplo-move defenders can sometimes be prevented from defending (because of a pin, for instance). The counting method still works, but you can't count the non-defending defenders.

  3. I just read through all the posts. I honestly am not following them 100%, but perhaps 60%.

    Could we summarize your view as:
    Counting is important (and here is an algorithm that is useful in practice), but you must consider potential tactics (duplo moves) that will interrupt the flow of captures.

    I'm still not done with basic one-square counting. :) I'm very focused right now on playing, analyzing games. Little chess time left over for fun.