This Mate in 2 Puzzle Forced FIDE to Change the Rules of Chess 😱

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In this video lesson, GM Igor Smirnov will show you a funny chess puzzle that forced FIDE to change the rules of chess.

Tim Krabbé composed this puzzle in the year 1972, which was meant to be a mate in 3. It uses a loophole in the rules of the game that was present during those days. This eventually forced FIDE to change the rules. To be specific, it used the loophole called vertical castling.

Back then, the definition of castling was “It moves the king 2 squares towards the rook, while the rook takes the square that the king has crossed”. And because of this loophole, the castling rule was then updated such that the king and the rook are in the same rank (so that only horizontal castling is possible).

► Chapters

00:00 Funny Chess Puzzle
00:08 Composition by Tim Krabbé in 1972
00:24 Can you solve this puzzle?
01:16 FIDE changed the rules after this
02:00 (Vertical) long castling?!
03:00 Loophole in chess rules
03:10 Can you find the mate in 2?

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  1. Bishop literally anywhere is the solution

  2. ► Chapters

    00:00 Funny Chess Puzzle

    00:08 Composition by Tim Krabbé in 1972

    00:24 Can you solve this puzzle?

    01:16 FIDE changed the rules after this

    02:00 (Vertical) long castling?!

    03:00 Loophole in chess rules

    03:10 Can you find the mate in 2?

  3. What could be the notation for vertical castling? O-O-O-O-O-O? 🤔

  4. Awesome keep it coming 👏 👌 👍 💯 💪 🙌

  5. That's how the en passaint rule appeared?! I did not watch the vid yet 🙂

  6. I guess it impossible, unless there was a rule of this kind: When promoted, the piece can be placed in every available square in the promotion column; so Rf1+ Kg2 Qe2#, or …Ke3 Qe2#

  7. I’d call that more of a clarification than a change in the rules. I believe that the intention was always to have castling on the back rank and that the rule written simply omitted that assuming it was understood.

  8. can we say that the rook moved when it was a pawn ?!

  9. Mate in 2: Qe5+, Kb4, Qa5#. Correct?
    I am new to your channel, and am a recent returnee to playing chess. Thank you for your videos.

    <<Castling consists of moving the king two squares towards a rook, then placing the rook on the other side of the king, adjacent to it. It is not allowed to move both king and rook in the same time, because "Each move must be played with one hand only." Castling is only permissible if all of the following conditions hold:

    – The king and rook involved in castling must not have previously moved;

    – There must be no pieces between the king and the rook;

    – The king may not currently be in check, nor may the king pass through or end up in a square that is under attack by an enemy piece (though the rook is permitted to be under attack and to pass over an attacked square);

    – The castling must be kingside or queenside as shown in the diagram.>>
    So this last item was introduced because of the loophole.

  11. This puzzle is truly beautiful it's the kind of position on television one person will say check! and the other person will say checkmate!! Kd6!! Threatening Qb7 mate. Any check by Black's rook can be blocked by White's Bishop! Leaving mate by White's rook

  12. the rook of the castle dont have the right to move before castle

  13. 1. Kd6 leads to mate in 2 no matter what the black does.

    1. Kd6 Rg6+ 2.Be6#

    1. Kd6 Rd3+ 2.Bd5#

    1. Kd6 c5 2. Qb7#

    1. Kd6 Kb6 2. Bc2#

  14. I owned Tim Krabbé's book, it was hilarious!

  15. Hmm I'm thinking Ba4+ (double check).
    King has to go to A5 or a6, after which Bb5#.
    But Slav Kevin seems to have another solution.

  16. When I saw the underpromotion, I had a feeling it was going to have to do with castling rules. I still didn't get it.

  17. That rook did move already during the game! It used to be on the side of the board or at another table.

  18. me explaining to the arbiter that en passant is forced

  19. King d6, black rook d3 check to white forced/anyother move is checkmate due to queen b7,whote bishop to d5 blocking check and giving instant checkmate

  20. I’m glad you highlighted this vertical castling rule that was made obsolete. I was drain on a puzzle some years ago and that was the solution: to vertically castle.

  21. Bishop to d5 or e6 or f7 is the checkmate in the given puzzel.

  22. Solution of puzzle: Qe5+ Kb4 (only move) Qa5#

  23. Bxf7 is mate in 1 at the end:)) if I did the math right

  24. 1. Q e5+ does not work because of c5 blocking check.
    therefore you need to play: 1. Ra5+ Kxa5 and 2.Qa3# thats how you do it there is no other way

  25. Puzzle Answer

    1 – kd6 …….
    anything mat coming

  26. Igor; Tell these people i'm correct on this one.
    Ra4, and now there's two mates black has to prevent: Bc2 and Qb4…..if he bring Rg4, then Bc2….and if his bishop takes b1 then game over with Qb4….

  27. Q-e5ch, K-b4: Q-a5 mate. If P-c5 then Bxf7 mates by discovered check.

  28. I’ve never heard of vertical castling, and that’s interesting that FIDE needed to change the rules to prevent its occurrence. 😊

  29. Great puzzle, great anecdote! Thanks.

  30. Bxb1 stops a “discovered checkmate” by moving the white bishop first. Hmm 🤔

  31. If white bishop takes blacks pawn isn't that ck mate in 1 or m I missing something?

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