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. *Arbiter comes over "Technically correct, the best kind of correct"

  2. We have all explored all the variations and no one has found a forced 2 move mate. I think maybe Igor is pulling a joke on us. He`s probably laughing his ass off watching us trying to solve an impossible problem.

  3. I have some solutions to the puzzle depends on which piece black moves after Kd6. 1st Kd6-Kb4 2nd KxPc6 mate. 1st Kd6-Rd3 2nd Bd5mate. 1st Kd6-Kb6 2nd Bc2mate. 1st Kd6-BxRb1 2nd Qb7mate. 1st Kd6-Rg4 2nd Qb7mate Everything depends on which piece they move after U move Kd6. 1more 1st Kd6-Pc3to Pc2 2nd Qb7mate. There was more than 1 sollution to that puzzle. If I made a mistake let me know it's after 2am right now don't know if my brain is still working 🙃

  4. Great !!!!! Great !!!!!! What a Great Puzzele maker !!!! I salute him !!!!. In my chess life I don't expect it, this type of LEGALLY MATE !!!!

  5. GM Igor 2 moves is not possible because the black rook block the discover check. Key move
    Rook a4 rook g4
    Bishop C2+ rook b4
    Queen x rook +mate 😁

  6. First move is White Bishop to C2+, Black King must move to C4, then White Rook to A4, checkmate!

  7. This is why most speedrunners use an earlier version of chess, before wrongcastle was patched out.

  8. That is the cleverest chess puzzle I have ever seen since it took advantage of a loophole in the rules! Did anyone ever figure out the solution on their own?

  9. This idea was discovered much earlier, already. See (not available in English)!

    Here's an anecdote regarding very long castling. I cannot remember where I have read it, though. In over the board blitz tournaments there is often not enough space for the player and they sometimes are sitting very close to each other.
    In such a tournament a player who had already lost one of his rooks used his neighbour's rooks to perform a VERY long castling. A few seconds later his neighbour wondered why one of his rooks had disappeared. Probably one of those "true" anecdotes…

  10. Why not after you promote to queen/rook, if the king goes g7, white Ke2, d4… RAg8#? Or after you promote to rook, if black goes …d4 reply with Re2 —- w/c guarantee the threatmate Rf8?

  11. Lame to change the rules of chess ! Why would they want to change it ! It's perfectly fine and cool LOL ! Disclaimer I am not a chess player ! Who knows maybe some king in ancient times actually used this trick ! 😉 =D

  12. Mate in 3 moves before FIDE's update about castling rule, with Pam–Krabbé castling rule.

    – if gxf3, e8=Q+ or e8=R+, Kd3, O-O-O#;

    – if d4,
    e8=Q+, Kd3, Qe2# or O-O-O#,
    e8=R+, Kd3, O-O-O#;

    – if Kxf3, e8=R,
    if Kg2, O-O-O-O-O-O#/Vertical Castle (Ke3 and Re2)#,
    if d4, O-O#;

    – if Kd3,
    if Kc2, O-O-O-O-O-O#/Vertical Castle (Ke3 and Re2)#,
    if d4 or gxf3, O-O-O#,
    if Kc2, Qe2#,
    if d4, Qe4# or Qe2# or O-O-O#,
    if gxf3, O-O-O#.

    Mate in 4 moves after FIDE's update about castling rule, without Pam–Krabbé castling rule.

    – if gxf3, e8=Q+ or e8=R+, Kd3, O-O-O#;

    – if d4,
    e8=Q+, Kd3, Qe2# or O-O-O#,
    e8=R+, Kd3, O-O-O#;

    – if Kxf3, e8=Q,
    if Kg2, Qe2+, Kxh1, Kd2# or O-O-O#,
    if d4, Qe2# or O-O#;

    – if Kd3,
    if Kc2, Qe2#,
    if d4, Qe4# or Qe2# or O-O-O#,
    if gxf3, O-O-O#.

  13. Last puzzle:
    – if Rd3+, Bd5#;
    – if Rg6+, Be6#;
    – if Kb4, Kxc6#;
    – if Kb6, Bc2#;
    – if f5, Ba2# or Bd5# or Be6# or Bf7# or Bg8# or Qb7#;
    – if Bg8, Ba2# or Bd5# or Be6# or Bxf7# or Qb7#;
    – if any other black legal move, Qb7#.

  14. Ba2 is even mate in 1 in the second puzzle.

  15. This patch sucked I want the devs to add this back

  16. wait, is this puzzle from a real game? It's unclear if they're talking about fischer and spassky's game or just a specifically made puzzle for vertical castling

  17. Never in my life I have heard of this strange castling demonstrated in this video.

  18. Bishop literally anywhere is the solution

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