Author: leonid
Date: 03:54:14 02/16/00
Go up one level in this thread
On February 16, 2000 at 04:11:43, Andreas Stabel wrote: >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 As I see now it was much more profound that I expected. I was really amazed with the 10 moves mate and puzzled when found that the second position goes even far. Only Marxen was able to go down to the solution. I know by experience that finding position for more that 7 moves ahead is really tough. Was never ready (and maybe able) to create the position by observing and thinking about it. Everything that I did was realized through specially dedicated logic, for the sake of making it work. Regards, Leonid.
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