24 Jun '13 22:57>
Checkmate is impossible?
Originally posted by woodypusherThis was thought to be impossible until a computer program worked it out. It requires more than 30 moves, however, so, according to tournament rules, this would be a draw. I doubt any human could reproduce the moves.
Checkmate is also impossible to force with K+N+N v K
Originally posted by moonbusForced being the operative word.π
This was thought to be impossible until a computer program worked it out. It requires more than 30 moves, however, so, according to tournament rules, this would be a draw. I doubt any human could reproduce the moves.
Wiki has a good article on mate with 2 knights: it is possible if the opposing K is poorly placed.
https://en.wikipedia.org/wiki/Two_knights_endgame#CITEREFSeirawan2003
Originally posted by moonbusYou are right Moonbus.
This was thought to be impossible until a computer program worked it out. It requires more than 30 moves, however, so, according to tournament rules, this would be a draw. I doubt any human could reproduce the moves.
Originally posted by moonbusThe article you quoted doesn't agree with your statement. π
This was thought to be impossible until a computer program worked it out. It requires more than 30 moves, however, so, according to tournament rules, this would be a draw. I doubt any human could reproduce the moves.
Wiki has a good article on mate with 2 knights: it is possible if the opposing K is poorly placed.
https://en.wikipedia.org/wiki/Two_knights_endgame#CITEREFSeirawan2003
There are also checkmate positions with the inferior side's king on the edge of the board (instead of the corner), but again they cannot be forced. (my bold)
Originally posted by SwissGambit[/b]Thanks for checking this. I was amazed and doubtful at the same time, and it looks like doubt won.
The article you quoted doesn't agree with your statement. πThere are also checkmate positions with the inferior side's king on the edge of the board (instead of the corner), but again [b]they cannot be forced. (my bold)
Originally posted by moonbusThanks for clarifying your other post.
I vaguely recall an article in an IT journal, not a chess journal, some years ago, claiming that the K+2N vs K problem had been solved. Alas, I can find no reference to this on the Internet. As I recall, the program ran for several days (well over tournament time limit) and the mate required many more moves than the 50-move draw-limit, of which all but the l ...[text shortened]... nd made mistakes (drawing in won positions), we mere mortals may accept that K+2N vs K is drawn.
Originally posted by ChessPraxisIt is furthermore useful to distinguish impossible, possible, and forced. Checkmate with K+2N vs K is possible, though not forced (for humans within tourney limits), whereas checkmate w/ K+B or K+N vs K is impossible.
Thanks for clarifying your other post.
Originally posted by moonbusWow...when most people put their foot in their mouth, they tend to pull it out at some point... π²
It is furthermore useful to distinguish impossible, possible, and forced. Checkmate with K+2N vs K is possible, though not forced (for humans within tourney limits), whereas checkmate w/ K+B or K+N vs K is impossible.