I wanna ask, is there any specific tactics on this ending. In one of my game i got KQ & can't mate my opontent KR becose his king was close his rook. Anyway is this KQ is always winnable vs KR?

Enter your positions into:

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

and let God do the analysis.

Win in 25 moves. 

Eternal, did u found this solutiom urself? Maybe some1 got some tricks about this position... When i try this vs Computer i always draw becouse 50 moves or repetition :(

No - I used the link the other poster provided.

It does look like a very tough ending, and there's no easy forumula for it.  Almost looks like you have to keep checking with the hopes of separating the King from the Rook, or your opponent blundering.

I find pinning the rook to the king helpful. It buys you a move!

to make it much tougher:

if opp is tablebase-equipped then opp will sometimes deliberately separate K from R, and you'll find that you can do squat about it! [flying-rook defence] - unless of course you have studied that...

but master Q v R *without* tablebases first :) - that will do against unaided humans, at least ...

normajeanyates wrote:

to make it much tougher:

if opp is tablebase-equipped then opp will sometimes deliberately separate K from R, and you'll find that you can do squat about it! [flying-rook defence] - unless of course you have studied that...

but master Q v R *without* tablebases first :) - that will do against unaided humans, at least ...

 on the contrary, separating the rook will drop it in a few moves, typically just like in the example posted above. the best chance of making the 50-move limit is to defend with 3rd rank defence, then 2nd rank, then philidor's position, and hope the opponent doesn't know the technique well enough thus wasting too much time.

about the topic, there are various very typical tactics and strategies in Q vs R mate, many of them visible in the example posted above. but I doubt it's allowed to give any specific advice on a game in progress on this site, so I won't go into it. but it's definitely quite hard, takes a lot of practice, and always won for the attacker, unless the queen drops or stalemates right away.

wormstar,

Please, that defence was unknown to humans; It was discovered soon after Ken Thompson came up with the K+Q v K+R tablebase. Initially international masters could not defeat this tablebase in 50 moves (though the longest mate is 35 moves).

The strategy of when-to-separate-K-and-R appears to be NOT human learnable.

I could give examples but why waste my energy when 'everyone' except you seems to know about it...

So try this. Play your strongest program, WITHOUT tablebases; against your WEAKEST tablebase-accepting-program, Give the latter the following tablebases: KQKR, KQK. That will do.

Give your strongest the position:

8/8/8/8/2r5/8/2k5/K6Q w - - 0 1

It is mate-in-35. But your non-tablebase-program will NOT be able to mate in 50.

Look at the defender's [weak program with those two tablebases] moves. You will find some flying-rook moves [ie deliberately separating K and R.]

Thank you.

Or search the internet. Look at wikipedia. Search rec.games.chess archives ... It is all there..

btw Q v R is mate in at most 35. The example in the above post needs all of 35 moves against best defence, but only 25 or so if opp doesn't play flying-rook moves at appropriate times; i.e. if opp is human, however strong.

Strange, all this was discovered back in 1992...

Purchase John Nunn's 'secrets of pawnless endings' - read up on K+Q v K+R. You think you know better than GM Nunn [also youngest person since lord kelvin to be admiited as a student to Oxford] - then - why are you not a GM ?????

I've found nice video about this kind of endgame:

http://www.youtube.com/watch?v=9kMbYvKumHc

"Eureka!" whats your name again?  

normajeanyates wrote:

The strategy of when-to-separate-K-and-R appears to be NOT human learnable.

 so what's the point in bringing it up? if it can't be learned, it's completely useless. just like most tablebase results.

I don't know what you're rambling about john nunn or me not being a GM. I can mate Q vs R against fritz in blitz speed (I posted a typical example of this ending in the endgame forum a few days ago, if anybody's interested), I don't need to know it better.

I bring it up because the strategy to win against the 'incredible flying rook defence' aka 'the 3rd line defence' or prosaically 'tablebase defence' IS:

EMINENTLY human-learnable.

You can beat fritz (plus tablebases) with K+Q v K+R? ???Well, then pigs can fly and cows can jump over the moon...

If only wishes were horses ...

 MyNameIsLuke, great video! [and some other great chess-videos linked to that page] - just download them using keepvid.com in case they disappear ;)

Thanks!

normajeanyates wrote:

I bring it up because the strategy to win against the 'incredible flying rook defence' aka 'the 3rd line defence' or prosaically 'tablebase defence' IS:

EMINENTLY human-learnable.

You can beat fritz (plus tablebases) with K+Q v K+R? ???Well, then pigs can fly and cows can jump over the moon...

If only wishes were horses ...

 for your enjoyment, I just blitzed a typical schoolbook example of 3rd rank defence against fritz. and no, I didn't play against tablebase. there would be no point, as only engine users could put up a defence like that. (btw, about that "flying rook defence" of yours, google can't find a single hit except this thread. can you give a link?)

big deal, with that position! try the position I gave. [if you can't read fen, learn it.]

try 'defense' the US spelling. and try google groups - rec.games.chess - search there

Now stop bothering me.

PS search 'roger poehlman' in 'google groups' -> rec.games.chess . search 'queen v rook' 'tablebase' 'tablebases'. Lokk up wikipedia. And stop bothering me.

normajeanyates wrote:

big deal, with that position! try the position I gave. [if you can't read fen, learn it.]

try 'defense' the US spelling. and try google groups - rec.games.chess - search there

Now stop bothering me.

PS search 'roger poehlman' in 'google groups' -> rec.games.chess . search 'queen v rook' 'tablebase' 'tablebases'. Lokk up wikipedia. And stop bothering me.

 frankly, it seems to me like you know absolutely nothing about Q vs R mate. you obviously don't even know what the 3rd rank defence is, and keep bringing up stuff which you can't back up. you're talking loud but saying nothing, where as I have already proven that I can walk the walk. I won't waste another word conversing with you.

b****y ignorant c*****s..