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Favourite Chess Tactics/Games/Random Positions - hamish olson - 02-02-2013

Just wondering what peoples favourite chess games/puzzles/whatever were - doesn't have to be anything amazing or anything flashy (although I wouldn't complain!)? Also curious as to how much of peoples reason for playing chess is the aesthetics and how much is competition or other stuff? For me a huge part of the game is about the beauty of it (although I am also pretty competitive about it).


Re: Favourite Chess Tactics/Games/Random Positions - hamish olson - 02-02-2013

a couple of positions that I saw in a book recently (Play Like a Grandmaster by Kotov) that I thought were really amazing (and sort of inspired me to start this thread):
[Image: 2otjs7c05gs.png] Black to play and win (answer in white - highlight it to see it) 1...Qxb4+2.Bxb4Rd2!!

white to play and win : [Image: 287ug6mewnk0c.png](answer in white)1.Bxd5cxd5 2.Nf6+Kh8 3.Qg6!!Qc2 4.Rh3!


Re: Favourite Chess Tactics/Games/Random Positions - Keith Ruxton - 03-02-2013

Interesting thread. One of my favourite puzzles is a game where the normal rules of chess apply but there is one additional rule: no piece can move from a square of one colour to a square of a different colour (so knights can never move, bishops work as normal etc.)

The position is a black king on e8, white king on e1, white pawns on f2 and d2 and a white bishop carelessly placed between e3 and e4. The question is: which square does the bishop stand on, e3 or e4?


Re: Favourite Chess Tactics/Games/Random Positions - Donald Wilson - 03-02-2013

Keith's white bishop is on e3.

Since pieces cannot move to a different-coloured square, they cannot capture a piece on a different coloured square (except in the case of en-passant captures - that's a complication, but it doesn't actually affect the outcome). So there are basically two wars being fought in parallel - one between the white-square pieces and one between the black-square pieces. Neither war can continue beyond the point where all the pieces of the appropriate colour on one side have been captured - the other side must have at least one piece of that colour remaining.

In the puzzle, all black's black-square pieces have been captured. But white's king and two remaining pawns (which are all black-square pieces) cannot have moved, and therefore cannot be responsible for the capture of any of black's pieces. The only piece that can have captured black's last black-square piece is the white bishop, so it has to be on a black square - therefore it is on e3, not on e4.


Re: Favourite Chess Tactics/Games/Random Positions - George Murphy - 04-02-2013

Basically, this is an example of retrograde analysis. Usually in chess problems, the composer strives to restrict choice. If the WB were on e3, then W would have had a choice of three captures on his last turn. That would normally be regarded as a constructional flaw. So, to conform with the stipulation, I'd say the WB must be on e4.

BUT, that seems rather pointless. Surely, it would be more convincing if the WB were to find itself on e6? There would then be a correlation (symmetry) between e3 and e6 - incidentally reflecting the struggle/campaign conducted on W/B squares. More to the point, with a WB on e6, the BK would be stalemated. That seems more aesthetic and therefore fitting.

So, my question is: did Keith make a typo? Did he mean e6 rather than e4? Bit of a giveaway, though, to actually specify e6 and e3.


Re: Favourite Chess Tactics/Games/Random Positions - George Murphy - 04-02-2013

From abstract to practical. The WPs on d2 and f2 form a barrier. This plus the stipulation that the WK cannot step from a W square to a Black means that the WB must end up on e4 in order to conform with Keith's stipulated choice between e3 and e4. If the WB were forced to settle on e3 to defeat one or other threat, then a capture by d2 or f2 would have been equally possible. So, the WB must be forced to choose e4 - not e3. That means that the Black Rook originally from a8 must be threatening mate from e4. (The BQ is confined to Black squares.) The WK cannot step onto a white square (d1/f1) to evade the check. So, the WB is forced to capture on e4.

So, that's the solution. But, a Black Rook could equally threaten mate from e6, when a WB capturing it would stalemate the Black King. That seems to me to be an improvement, but I'm not setting the puzzle. Note, too, that another stipulation could have been set. Black could have been required to help White impose a selfstalemate. For this purpose, the move ...e6, met by B x e6 would have served just as well.

Wonder if it might have been possible to create a position in which the two sides (W & B) could have been required to effect a reflex-selfstalemate? That's when the side with the move is required to effect a stalemate if such is possible.


Re: Favourite Chess Tactics/Games/Random Positions - andyburnett - 04-02-2013

George Murphy Wrote:From abstract to practical. The WPs on d2 and f2 form a barrier. This plus the stipulation that the WK cannot step from a W square to a Black means that the WB must end up on e4 in order to conform with Keith's stipulated choice between e3 and e4. If the WB were forced to settle on e3 to defeat one or other threat, then a capture by d2 or f2 would have been equally possible. So, the WB must be forced to choose e4 - not e3. That means that the Black Rook originally from a8 must be threatening mate from e4. (The BQ is confined to Black squares.) The WK cannot step onto a white square (d1/f1) to evade the check. So, the WB is forced to capture on e4.

So, that's the solution. But, a Black Rook could equally threaten mate from e6, when a WB capturing it would stalemate the Black King. That seems to me to be an improvement, but I'm not setting the puzzle. Note, too, that another stipulation could have been set. Black could have been required to help White impose a selfstalemate. For this purpose, the move ...e6, met by B x e6 would have served just as well.

Wonder if it might have been possible to create a position in which the two sides (W & B) could have been required to effect a reflex-selfstalemate? That's when the side with the move is required to effect a stalemate if such is possible.

Sorry, lost me there completely George. Where did the rook and mate threats appear from? =|


Re: Favourite Chess Tactics/Games/Random Positions - George Murphy - 04-02-2013

Andy,
Keith described the final position, asking us to decide which square the WB stood on - e3 or e4. Retrograde analysis - taking account of the restrictions Keith imposed - yields the answer.

It's all logical.


Re: Favourite Chess Tactics/Games/Random Positions - Donald Wilson - 04-02-2013

George,

Keith didn't say that the last move was a capture - the last capture may have occurred many moves earlier.

And your solution totally fails to explain the absence of black pieces on black squares.


Re: Favourite Chess Tactics/Games/Random Positions - George Murphy - 04-02-2013

Donald,

We're discussing an artificial position - not a normal game. If Knights cannot move, how do you think they all disappeared from the board? Obviously, they were captured on their original squares. Now, let's just take the WN on g1. It can only have been captured by a Black piece moving on Black squares. That restricts the choice to BQ, BB (f8) or BR (h8). Moreover, the WR (h1) would not have been able to recapture on g1 (wrong colour of square). Furthermore, if the capture on g1 were effected by the BQ or BR (h8), the WB (f1) would either have had to be on f1 or available to intervene on f1 - to avoid check forcing the WK to move away from e1.

So, you can see very readily that it would be impossible to reconstruct every move of the game - known as a proof game.

All we can do is meet the requirements of the position and conditions that Keith imposed. The moves leading up to that position - especially the earlier ones that led to mass exchanges and consequent simplification - have to be legal, not rational or optimal.