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Suppose both the kings are left in a fairly neutral positions with just rook at one side and a bishop at the other side. What is the outcome if both the sides play correctly?
Can a side with only bishop claim a draw?

Related:

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  • Well the side with the bishop certainly can't claim a draw unless there is a another reason, such as repetition of position or the 50 move rule. My understanding is it is typically a draw, but I'll leave that part to the endgame tablebase masters.
    – Ian Bush
    Feb 16, 2023 at 8:19
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    Just for fun, the longest win in a won position takes 29 moves: gilith.com/chess/endgames/kr_kb.html Feb 16, 2023 at 10:01
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    For future reference: All endgames with 7 or fewer pieces on the board (incl. both kings and all pawns) are "solved" - you can put them into Lichess's analysis board, click the little book icon in the lower right, and it will tell you exactly which moves win/lose/draw.
    – Kevin
    Feb 16, 2023 at 20:45

2 Answers 2

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See Pawnless Chess Endgame on Wikipedia:

Rook versus a bishop: this is usually a draw. The main exception is when the defending king is trapped in a corner that is of the same color square as [their] bishop (see Wrong bishop#Rook versus bishop). If the defending king is trapped in a corner that is the opposite color as [their] bishop, [they draw] (see Fortress (chess)#Fortress in a corner). See the game of Veselin Topalov versus Judit Polgar, where Topalov defended and drew the game to clinch a win of their 2008 Dos Hermanas match.

Mate is possible, and the side with the Bishop definitely cannot claim a draw (until 50 moves is up).

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The side with a bishop can't immediately claim a draw as there are opportunities for checkmate.

At lower levels, the defense isn't trivial either and it's in fact impossible if the side with the bishop can't manage to one of the "safe" corners (the ones with the color opposite to that of the bishop)

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  • "if the side with the bishop can't manage to one of the "safe" corners (the ones with the color opposite to that of the bishop)" I couldn't understand this. I think some words are missing? Feb 17, 2023 at 16:48
  • @KarlKnechtel let's say you have a dark-squared bishop. If your king can go to a light-squared corner, it's possible to draw. If he's pushed into a dark-squared corner instead, the position will be lost
    – David
    Feb 17, 2023 at 17:03
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    I can't understand what "manage to one of the corners" is supposed to mean. Was that supposed to be "manage to protect one of the corners"? "Manage to get to one of the corners"? Something else? Also, are you actually talking about the player? or the bishop? or the king? Feb 17, 2023 at 20:01
  • @KarlKnechtel The king won't be able to stay in the middle of the board forever. At some point the side having king and rook can force the enemy king into the side of the board. If they can arrive to the right corner, they'll hold a draw but if they end up in the wrong one thye'll lose
    – David
    Feb 18, 2023 at 1:01

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