Mate with king+rook vs. king+bishop

Hi guys,

sorry if this has been asked here already, but I'm a newbie and I couldn't find the answer here on anywhere on the internet.

My question is: Is it always possible to mate king+rook vs king+bishop(no pawns)? If yes, are there any guides, how to mate?

Thanks

thanks for your reply, however I still dont get it :D

In a following position, how can I decide whether it's a draw or a win? In general, what are the conditions for a white to win?

A general rule on when white can win can be hard to say. If the position is such that white can combine mate threats with threats against the bishop and black can not get around that then you have a winning condition. But normally king+rook vs. king+bishop is a draw.

Here is a white win position I found on the net, a difficult one I would say, it is a mate in 29: http://www.gilith.com/chess/endgames/kr_kb.html

You can check out specific positions here: http://www.k4it.de/index.php?topic=egtb&lang=en

It is not an easy end game I would say.

If you are the one with the rook you can try out and see if you can win the bishop (or check mate) before 50 moves are up, or you can decide to not bother and offer a draw, I think that in most cases it would be a drawn position anyway. Before you offer a draw you might want to at least play out some moves just to look for tactics and get some idea of the possibilities.

If you are the one with the bishop you would of course go for the draw, so resigning is not an option unless you end up in a position with no rescue. Look for tactics, especially look for possibilities to pin the opponent's rook to his king with your bishop.

thanks for a help!

You are welcome!

There is a type of position where the player with the rook has a winning position, so it is a good idea to know that one (I just had a look in one of my chess books). So if you have the rook you would want that position, if you have the bishop you would avoid it. It is a position where the defending king is on the edge and the other king opposing it, and regarding the other pieces ... well it is easier to show a diagram, so I will do that.

Note in the diagram below that black has to keep his bishop on either the same file as the kings or on one of the adjacent files. So in this case black needs to keep the bishop on the e, f or g file.

It's usually a draw. It's a draw if the black king can reach a corner of the colour opposite to his bishop's. It can be won if the defender is forced to the back rank and cut from the saving corner (like in the example above.)

However, this endgame very seldom arises in practical play (there are often a couple of pawns left).

here is a video of how to do mate http://www.youtube.com/watch?v=8l_WUwwcIGI

Last time I had the bishop, I just kept my king on the same color and prevented black from getting opposition. It worked. 50 move rule.

The king has to be on a certain square, next to the opponents king, and the (box) that the rook has made has to be small, also if the box is somewhere where the bishop could go, then, no, but if its like your rook cant be attacked, then you have a chance of winning. I was once playing and it came down to a game where we both had a rook, but apparently, my opponents king was trapped into a box by my rook, but my king wasn't, so I kind of had the advantage. Also once your rook has cornered your opponents king, the best move would probably to sacrifice the bishop so the opponent can stay alive longer and maybe get the 50-move rule to work.

a capture cancels the 50-move rule

The 50-move rule doesn't matter a lot in this position. If you can hold out 50 moves with the bishop you can also hold out 500 moves. It's different in endgames with strategies that intrinsically require around 50 moves to execute.

There is some good news for the rook side though. You can never loose this endgame on the clock since there is no mating potential for the bishop side. That's different from the K+R vs K+N endgame

Yes, a capture does cancel 50 move rule but to make the king last longer.

I ended up losing my rook and taking the bishop and it ended in a tie

K and R vs K and B is a draw assuming the one with the bishop doesn't make a mistake.

It is a draw if the side with the bishop moves his king to a corner that is the opposite color of his bishop. In this position black moved his king to a corner that opposite the color of his bishop. He is stalemated since his bishop is pinned and he can't move his king.

I got this position in one of my games as the king and bishop but I ran out of time before it could be a draw .