Sunday, March 06, 2016

Protectors of the attacking square

When I analysed  M1-h (Mate in one - hard), I found four subtasks that are the main time eaters. Lain has made four great exercises for them:
  • Find blocking pieces
  • Find escape square creating piece
  • Find pinning pieces
  • Find protecting pieces
So far, I have tried only two of these seriously.  I think Find All Pinning Pieces is a great exercise already, and it seems improvable too. But then I stumbled on a lot of problems with Find All Protecting Pieces. Take for instance the next diagram:

White to click on all black pieces that prevent mate
 Solution: [b5,c8,h7]
In order to solve this position, you need to accomplish the following subtasks:
  • Identify all squares were white can give a check
  • Identify which checking square might be a potential mate
  • Identify which black pieces protect the mating square
If you look at it, solving the M1-h has now become a subtask of the task "Find All Protecting Pieces". And indeed, to do this exercise takes even more time than M1-h.

The problem is, that the task can't be done in isolation. We shouldn't have to worry about potential mate.

What would be the ideal situation?
There are four elements here that are relevant:
  • The attacker (the begin)
  • The attacking square (the road)
  • The target (the end)
  • The protector of the attacking square
Every element needs a dedicated exercise.
Identify the attacker and Identify the target are covered by the exercise "Find all attacked pieces" (FAAP) of Chessgym.
Identify the attacking square is covered by FAC (Find All Checks). The target is always the king here, so the attacking square equals the checking square, but that's ok.

You can't do FAC without mastering FAAP.
You can't do IAPP (Identify All Protecting Pieces) without FAC.

This means, the base for IAPP should be FAC and not M1, as it is now.
The same is true for IABP (Identify All Blocking Pieces).

Logically, even Identify the Pinning Piece should be based on FAC and not M1

Only FESCP (Find Escape Square Creating Pieces) is rightfully based on M1.

Anyone still following me?
Lain, what do you say?


  1. Whats about a "Find all Save Checks" FASC ?
    Or a "Find all save attacks" ( as 2.step of chessGym "attacks" ) ?

  2. I like the new classification, with FAC as the new base. I don't see nothing wrong at the moment. There is no problem like M1-h being a subtask of the subtask of himself now.

    The only thing that worries me is that IAPP/IABP are improvable or not, maybe they are harder than M1-h? but I'm not the expert in this area...

    1. Your worry is my worry too. Both are not improvable, since they are more complex than M1-h. I hadn't see that one coming. There is now an extra step that you must solve the position as a M1-h first, before you can know if a protecting piece protects against mate.

      What we need is a FAC-like exercise, identifying the pieces that protect a checking square. The fact that a mate is prevented by the protection of the checking square is unnecessary complicating the exercise.
      The same for blocking pieces.

      I wonder if the code you have written is flexible enough to generate such exercises too?

    2. What you need is a FASC "Find all save checks" save means that the checkgiving piece cant be taken

    3. It is, but generate the FEN list from M1-h positions would take a little (I can't reuse the last FEN list for IAPP/IABP). And I can't begin to modify the code immediately.

    4. There are several ways the checks can be disrupted: A pinned attacker, a protected attacking square and a blockading piece that can interpose the line of attack. All need to be trained in isolation. And maybe combined later.

  3. Oh, great idea! What about creating the tasks:

    1) FIND all defence from check by BLOCKING a line of attack
    2) FIND all defence from check by CAPTURING the attacking piece

    In the task number 1 should click at the squares (pieces) they could block/interpose the line of attack (if the Knight gives check - these positions should be excluced), in task number 2 you have to click at the squares (pieces) which are able to capture the attacking (checking) piece. I think these excercises could give another boost to our testing process.

    BTW. FIND all defence from check by ESCAPING to a safe square (the task has already been created), it is FAES.

    1. If we try to improve m1 we should transform your suggestion to
      1) Find all checks which cant be blocked FACNB ( thats what we are looking for at m1 )
      2) Find all save checks FASC where the attacking piece cant be captured by the defender ( thats what we are looking for at m1 )

      At m1 we are looking for a move which is 1 and 2 and 3 at the same time

      But of course the base of 1) and 2) is FAC which is not easy to improve
      3) is seemingly good improvable

      Maybe we see the startegy of problem-composer, they chose subtasks which are hard to improve. m1-h is usualy not based on the reduction of the mobility of the king, quite often the king is already "stalemated".

  4. Tempo

    I am still following you. I like reading your posts VERY much! Anyway - as I have too much works to be done - I stay away from salt mines and practicing (testing) all the tasks and subtasks. I have simply done too much so far and I have to reast really well. Anyway - I am reading your articles and comments with great interest and very often! They are indeed really inspirational! Keep up good work.

    BTW. I will let you know when I come back to the tests. Probably in about 2-3 months from now. I keep fingers crossed on all the salt miners. If you have any questions or comments (related) to me - just go ahead!

  5. As more i do FAES as more i am convinced that it is a key skill. Its about the question: is that move "save" as Dan Heisman would probably say.

    Related exercises are
    Chess Minefileds (free of charge)
    Chessity's Route planer (Premiums only)

    you should only take a "grain of salt" and not several kilograms ;)

  6. I played Chess Minefileds for about 8-10 hours. These puzzles are not so demanding (challenging) to me. I get bored with these quite fast. Anyway I am looking forward to your score at M1e - I am really curious how much you can improve this task.

    If I had to solve/take a "grain of salt" and not several kilograms - I would have to live at least a few thousand years ;) :). I prefer doing quite much in a very short period - rather than being systematic and solving a few puzzles every day.

  7. the question is now : did 8h Minefild did help at other tasks?

    My performance at m1-e is not stabile, i have some healt problems my score jumps up and down depending on my health, but my peak performance is now 20 ( was 15 ) and still climbing ( sometimes )

  8. I do not know if Chess Minefileds helped me at other tasks. Why? Because there are two factors involved: 1) it was too easy, 2) it was too low number of excercises done

    I treated this excercises like some fun. Anyway there are many others (sub)tasks that need to be improved.