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  1. 18 Jan '13 19:18
    So, I recently got into my first R+B vs R endgame. I tried to do it in the 50 moves available, then offered a draw when it was clear that I couldn't mate in time. My challenge is, I know it is a technical win, but can YOU finish this off in the moves available against the best response without a box? I dropped some moves by repetition, but even still I don't think I could have finished it off in time. Answers on a postcard please

    The countdown starts at move 57...
    Game 9603028

  2. Standard member RJHinds
    The Near Genius
    18 Jan '13 19:49 / 1 edit
    Originally posted by morgski
    So, I recently got into my first R+B vs R endgame. I tried to do it in the 50 moves available, then offered a draw when it was clear that I couldn't mate in time. My challenge is, I know it is a technical win, but can YOU finish this off in the moves available against the best response without a box? I dropped some moves by repetition, but even still I don Ke5e4 Rh5h4 76. Ke4d3 Kb4b5 77. Bf5e4 Kb5b6 78. Kd3d4 1/2-1/2[/pgn]
    What I learned from my old book "Chess Self-teacher" by Al Horowitz is the general rule of thumb with endings without pawns is to cancel out like pieces and determine if what remains can result in a forced mate. In this case, we see that the pawn can be captured with check and we have the R+B vs R endgame. Since the Rooks can be canceled out and a lone bishop can't force a checkmate, the game should be a draw with best play on both sides.

    Wikipedia says the side with the bishop can force a win in certain position even though it is very difficult.

    http://en.wikipedia.org/wiki/Rook_and_bishop_versus_rook_endgame
  3. 18 Jan '13 20:06
    I knew that, thank you. The idea was to have a go and see if you can do it unaided...
  4. Standard member RJHinds
    The Near Genius
    18 Jan '13 20:42
    Originally posted by morgski
    I knew that, thank you. The idea was to have a go and see if you can do it unaided...
    I doubt if I could do it within 50 moves even if I could force it into one of the winning positions, because I have not studied this type of ending. If it happened OTB I would probably just agree to a draw.
  5. 18 Jan '13 21:08
    Originally posted by RJHinds
    I doubt if I could do it within 50 moves even if I could force it into one of the winning positions, because I have not studied this type of ending. If it happened OTB I would probably just agree to a draw.
    "You do not learn if you do not try" Morgski, 2013
    Trial and error is the best way to realise what you don't know. Studying comes later.

    Anyway, we digress. It is possible to win with this combo of pieces and unlimited moves, I could see a way to do it. Just not under 50. I want to know if that is because I messed up with my early moves, or whether this ending can only be done within the move limit in certain positions (e.g. defending king doesn't control the centre).
  6. Standard member RJHinds
    The Near Genius
    18 Jan '13 22:46
    Originally posted by morgski
    "You do not learn if you do not try" Morgski, 2013
    Trial and error is the best way to realise what you don't know. Studying comes later.

    Anyway, we digress. It is possible to win with this combo of pieces and unlimited moves, I could see a way to do it. Just not under 50. I want to know if that is because I messed up with my early moves, or whether this ...[text shortened]... within the move limit in certain positions (e.g. defending king doesn't control the centre).
    Okay, I tried it and I went over 50 moves without mating. However, I was able to get the other king to the edge of the board, but I could not figure how to get my king up close in opposition like in the diagrams shown in Wikipedia.
  7. Standard member ChessPraxis
    Cowboy From Hell
    18 Jan '13 23:12
    Tough one Morgski. I may be wrong, but if I remember correctly there are some instances where a forced win is possible, but it takes more than 50 moves. I think it was around 75 moves. FIDE changed their rule to 100 moves, then changed back to 50.
    Maybe someone else can correct me if I am wrong.
    (RJ if you think I am wrong, send me a game and we'll slap the snot outta each other over the board)
  8. 19 Jan '13 12:42
    Cheers CP, strange that a win is possible, but hardly ever within the move limit. I'll do some research...
  9. 19 Jan '13 13:42 / 1 edit
    Originally posted by morgski
    "You do not learn if you do not try" Morgski, 2013
    Trial and error is the best way to realise what you don't know. Studying comes later.

    What does that mean?
    You thought that you knew and when you didn't do it you realised that you didn't knew?
    I think it works the other way around: you study it because you know that you don't know it and when it comes in a game you do it(when and if it is winning).
  10. 19 Jan '13 14:10
    Originally posted by ChessPraxis
    Tough one Morgski. I may be wrong, but if I remember correctly there are some instances where a forced win is possible, but it takes more than 50 moves. I think it was around 75 moves. FIDE changed their rule to 100 moves, then changed back to 50.
    Maybe someone else can correct me if I am wrong.
    (RJ if you think I am wrong, send me a game and we'll slap the snot outta each other over the board)
    No you are not wrong.
    FIDE indeed changed the 50 move rule to 75 (according to Karsten Muller) but that decision was reversed.
    For the attacking side to win it is necessary to force the enemy king to the edge of the board so the 2 main defensive methods for the defensive side(Cochrane defense and Second rank defense) attempt of course to prevent exactly that.
    Philidor has shown when and how the attacking side can win.

    [Result "1-0"]
    [SetUp "1"]
    [FEN "3k4/4r3/3K4/3B4/8/8/8/5R2 w - - 0 1"]

    1. Rf8+ Re8 2. Rf7 Re2 3. Rh7 Re1 4. Rb7 Rc1 5. Bb3 Rc3 6. Be6 Rd3+ 7. Bd5 Rc3
    8. Rd7+ Kc8 9. Rh7 Kb8 10. Rb7+ Kc8 11. Rb4 Kd8 12. Bc4 Kc8 13. Be6+ Kd8 14.
    Rb8+ Rc8 15. Rxc8# 1-0

    The mating net that white sets appears in many middlegame positions too so it's a good pattern to be studied and recognised.
  11. Subscriber Paul Leggett
    Chess Librarian
    19 Jan '13 14:28
    Originally posted by Roper300
    No you are not wrong.
    FIDE indeed changed the 50 move rule to 75 (according to Karsten Muller) but that decision was reversed.
    For the attacking side to win it is necessary to force the enemy king to the edge of the board so the 2 main defensive methods for the defensive side(Cochrane defense and Second rank defense) attempt of course to prevent exactly t ...[text shortened]... ars in many middlegame positions too so it's a good pattern to be studied and recognised.
  12. Standard member RJHinds
    The Near Genius
    19 Jan '13 14:52 / 5 edits
    I will show only one variation to force the enemy king to the edge of the board with kings in opposition, because black can vary his move at several points and may be a little more stubborn, but I believe the king can still be driven to the edge of the board. It was easier to drive the king to the side of the board instead of to the top.

    Now if anyone can show how this can be forced into a winning position, then we will know if the original position is a draw or a forced win.



    Here are the two main wining position shown in wikipedia

    Philidor position



    Lolli position

  13. Standard member RJHinds
    The Near Genius
    19 Jan '13 16:08 / 1 edit


    Can black get a draw with Ka4 ???

    Looks like he can to me.
  14. 19 Jan '13 19:05
    Originally posted by Roper300
    What does that mean?
    You thought that you knew and when you didn't do it you realised that you didn't knew?
    I think it works the other way around: you study it because you know that you don't know it and when it comes in a game you do it(when and if it is winning).
    I meant that, for me at least, I don't fully understand the problem at hand unless I have had a go myself. Same goes for openings, when I was learning I could read all I liked about the Dragon, Scandinavian etc., but it was only by trying them that I learnt their strengths, weaknesses, and the holes in my understanding.
  15. 19 Jan '13 21:29
    Originally posted by morgski
    So, I recently got into my first R+B vs R endgame. I tried to do it in the 50 moves available, then offered a draw when it was clear that I couldn't mate in time. My challenge is, I know it is a technical win, but can YOU finish this off in the moves available against the best response without a box? I dropped some moves by repetition, but even still I don ...[text shortened]... Ke5e4 Rh5h4 76. Ke4d3 Kb4b5 77. Bf5e4 Kb5b6 78. Kd3d4 1/2-1/2[/pgn]
    Assuming no side makes an error, the position is drawn regardless of number of moves.

    Post game analysis I use this tool (although it only allows 6 pieces including kings). Take a look at this tablebase. It's an excellent tool.

    http://www.k4it.de/index.php?topic=egtb&lang=en