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Subject: Re: Mate in ...?

Author: Andreas Stabel

Date: 01:11:43 02/16/00

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On February 15, 2000 at 17:22:40, leonid wrote:

>On February 15, 2000 at 07:40:32, Andreas Stabel wrote:
>
>>On February 14, 2000 at 17:39:42, leonid wrote:
>>
>>>On February 14, 2000 at 11:29:23, Heiner Marxen wrote:
>>>
>>>>On February 14, 2000 at 05:08:22, Andreas Stabel wrote:
>>>>
>>>>>On February 13, 2000 at 18:02:20, James T. Walker wrote:
>>>>>
>>>>>>On February 12, 2000 at 10:18:44, leonid wrote:
>>>>>>
>>>>>
>>>>>>
>>>>>>This is from George Koltanowski's book "TV Chess".  It is a mate in 10 with 4
>>>>>>underpromotions to a Knight.  It is one of my favorites.  I was surprised to
>>>>>>find in the late 80's that the Fidelity Champion Sensory Challenger would solve
>>>>>>this problem in about 42 seconds.  Todays programs will solve this in less than
>>>>>>1 second.
>>>>>>
>>>>>>[D]7K/P1p1p1p1/2P1P1Pk/6pP/3p2P1/1P6/3P4/8 w - - 0 1
>>>>>>
>>>>>>Jim Walker
>>>>>
>>>>>This is a nice variation on the same position the I made from another
>>>>>variation on this position :)
>>>>>Note the nice queen moves at the end, and that promoting to a knight the
>>>>>third time will not work.
>>>>>
>>>>>[D]8/1p1p1p1p/3P1P2/pp5P/kp6/1p4P1/1P4P1/2K5 w - - 0 1
>>>>>
>>>>>Regards
>>>>>Andreas Stabel
>>>>
>>>>Ah, I like it!  It is a mate in 16.  Chest on P/133 with 10 MB hash table
>>>>needs 1.15 seconds to find the main variation:
>>>>
>>>> g4 h6 g5 hxg5 h6 b6   h7 g4   h8=N g3 Ng6  fxg6 f7    g5 f8=N
>>>> g4 Ne6 dxe6 d7 e5 d8=Q e4 Qb8 e3 Qxg3 e2 Kd2 =*= Qxe1 g3 Qa1#
>>>>
>>>>Complete solution tree in 1.67 seconds.  Wow.
>>>>
>>>>Heiner
>>>
>>>Now I see why my logic could not touch it. It is too deep to see. My mate logic
>>>goes only 13 moves deep. But compose position as deep as 16 moves is a real
>>>challenge. Well done!
>>>
>>>Leonid.
>>
>>Thanks, my only regret is that this is an illegal position. The configuration
>>of black pawns can never be reached in an actual game.
>>Notice the nice mate in 6 for white if black answers 1. g4 with 1... b6 !
>>
>>The position I made this problem from is the following with white to move
>>and win. Note that it is NOT a mate in n problem.
>>
>>[D]8/pp1p1p2/1p1P1P2/k7/8/1p4p1/1P4PP/2K5 w - - 0 1
>>
>>Here it will work to promote to a knight the last time also, but if you
>>choose to promote to a queen, the mate will be the same as in my mate in
>>16 problem. This is of course asuming that plays for a stalemate, and close
>>up the king position completely.
>>
>>Best regards
>>Andreas Stabel
>
>
>Sometime very impossible position is good to have when you write your logic. It
>permit to find, generally speaking, if logic work well. Position with 9 queens,
>6 rooks... I created many positions when I wrote my initial logic that generate
>legal moves. To see if everything goes well, positions that contain inevitable
>mate were ideal for debugging.
>
>Just by curiosity, how you reached your quit sofisticated positions, by "hand"
>or with usage of some program? Did you came to the creation of the position my
>way? I want to say that you started writing some logic and solving the positions
>was your way to find some responses. Or you just created your positions for fun
>since the beginning?
>
>Regards,
>Leonid.

The last of the positions above:
8/pp1p1p2/1p1P1P2/k7/8/1p4p1/1P4PP/2K5 w - - 0 1
was a problem I was shown some years ago. I liked it, but discovered that
it was not a forced mate because black doesn't have to play for a
stalemate. In addition I really love the version where you choose a
queen on the last promotion, so I started fiddling with the position, first
to make it a forced mate in as many moves as possible. When I had done
this I found that adding the pawn at b7 giving the position:
8/1p1p1p1p/3P1P2/pp5P/kp6/1p4P1/1P4P1/2K5 w - - 0 1
which is shown above, would force white to choose a queen on the last
promotion. This was just a lucky accident, but perhaps what makes this
mate in 16 a real beauty to me. The draw-back is of course that this
position could never be reached in a real game and that the version where
you choose a knight at the end, which is also beautiful, was lost.
Perhaps a small consolation is that the variation where black answers
1. g4 with 1... b6 gives a mate in 6 with a similar theeme.

I think the whole process of thinking about this position and fiddling
with it perhaps took 5-10 years :)

Regards
Andreas Stabel



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