Comments/Ratings for a Single Item
What about this situation (white to move):
+---+---+---+---+---+---+---+---+
8 | |:::| |:::| |:::| |:::|
+---+---+---+---+---+---+---+---+
7 |:::| P |:::| |:::| |:::| |
+---+---+---+---+---+---+---+---+
6 | |:::| |:::| |:::| |:::|
+---+---+---+---+---+---+---+---+
5 |:::| |:::| |:::| |:::| |
+---+---+---+---+---+---+---+---+
4 | |:::| |:::| |:::| |:::|
+---+---+---+---+---+---+---+---+
3 |:::| |:::| |:::| |:::| |
+---+---+---+---+---+---+---+---+
2 | |:::| |:::| |:::| |:::|
+---+---+---+---+---+---+---+---+
1 |:n:| |:::| |:N:| |:::| |
+---+---+---+---+---+---+---+---+
a b c d e f g h
If white b8=Q or b8=R, then stalemate. If b8=B, then I believe there is insufficient material for mate -- thus b8=K. I'm fairly sure that K+N can mate bare N. If not, add a B at g1. Two B on the same color + N vs N is still not promising, but K+B+N vs N is surely enough!
Hmm. A Problem with my previous post -- White could move their Knight, then on the following move promote the Pawn to Queen.
However, this situation ought to do it.
+---+---+---+---+---+---+---+---+
8 | |:::| |:::| |:::| |:::|
+---+---+---+---+---+---+---+---+
7 |:::| P |:::| |:::| |:::| |
+---+---+---+---+---+---+---+---+
6 | |:::| |:::| |:::| |:::|
+---+---+---+---+---+---+---+---+
5 |:n:| |:::| |:N:| |:::| |
+---+---+---+---+---+---+---+---+
4 | |:::| |:::| |:::| |:::|
+---+---+---+---+---+---+---+---+
3 |:::| |:::| |:::| |:::| |
+---+---+---+---+---+---+---+---+
2 | |:::| |:::| |:::| |:::|
+---+---+---+---+---+---+---+---+
1 |:::| |:::| |:::| |:::| |
+---+---+---+---+---+---+---+---+
a b c d e f g h
Since white better promote the Pawn or black will take it.
I guess that raises a follow-up question. What material is sufficient to force checkmate. Q + N vs N ? K + N vs N ? R + N vs N ? two Rooks + N vs N two Bishops (on opposite colours) + N vs N The Queen mate is easy and in fact the Queen could force mate on it's own without help from it's own Knight. I'm pretty sure the two rooks can do it. I'm not sure about the one Rook though. The King may be able to but I'd have to work it out. The two Bishops, probably, but again I'd have to work it out. Had anyone actually played this game. Are strategies similar to the conventional game, ie, control the centre, develop your pieces etc.
According to the Encyclopedia of Chess Variants, in Knightmate a K can mate a N unaided, so my solution to your challenge stands.
Valid point. However, this version of the problem, with white to move:
+---+---+---+---+---+---+---+---+
8 | |:::| |:::| |:::| |:::|
+---+---+---+---+---+---+---+---+
7 |:::| P |:::| |:::| |:::| |
+---+---+---+---+---+---+---+---+
6 | |:::| |:::| |:::| |:::|
+---+---+---+---+---+---+---+---+
5 |:n:| |:::| |:N:| |:::| |
+---+---+---+---+---+---+---+---+
4 | |:::| |:::| |:::| |:::|
+---+---+---+---+---+---+---+---+
3 |:B:| |:::| |:::| |:::| |
+---+---+---+---+---+---+---+---+
2 | |:::| |:::| |:::| |:::|
+---+---+---+---+---+---+---+---+
1 |:::| |:::| |:::| |:::| |
+---+---+---+---+---+---+---+---+
a b c d e f g h
Should do it. After b8=K, black Nb3 is forced. After white Kb7, the black N is pretty well trapped.
I ran end-game data-bases for this game, and it turns out that for the single-piece end-games only N+Q can force the royal Knight into checkmate. Not even a Rook suffices, and neither does a (Commoner) King. Any two-piece advantage can enforce checkmate, though, except N+N+N, but in Knightmate that is even outlandish as K+K+K in FIDE chess (but, by the way, easily beats K+R there!). In particular N+K+B is an easy win over a bare Knight, the position after b8(K) in the proposed problem is a mate in 10: 1. Kc7 Nb3 2. Nf3 Na5 3. Kb6+ Nc4 4. Bc5 Nb2 5. Kb5 Nd3 6. Be3 Nb2 7. Kb4 Nd1 8. Ba7 Nb2 9. Kc3+ Nd1 10. Kc2++
Any two-piece advantage can enforce checkmate, though, except N+N+NDoes that include N+B+B vs N when both Bishops are on the same color? If that's the case, then I still haven't come up with a case where promotion to Commoner is required.
White: Knight (d3) and Pawn (e7), Black: Knight (a6) and Rook (d8) +---+---+---+---+---+---+---+---+ 8 | |:::| |:r:| |:::| |:::| +---+---+---+---+---+---+---+---+ 7 |:::| |:::| |:P:| |:::| | +---+---+---+---+---+---+---+---+ 6 | n |:::| |:::| |:::| |:::| +---+---+---+---+---+---+---+---+ 5 |:::| |:::| |:::| |:::| | +---+---+---+---+---+---+---+---+ 4 | |:::| |:::| |:::| |:::| +---+---+---+---+---+---+---+---+ 3 |:::| |:::| N |:::| |:::| | +---+---+---+---+---+---+---+---+ 2 | |:::| |:::| |:::| |:::| +---+---+---+---+---+---+---+---+ 1 |:::| |:::| |:::| |:::| | +---+---+---+---+---+---+---+---+ a b c d e f g h
leads to 1.exd8(K) Nb8 2.Kc7 Na6 3.Kb7 mate! Promotion to a Queen is stalemate. To meet Robert's challenge in the first Comment, we need to verify that promotion to either Bishop or Rook in this position will also lead to a draw. This 'capture promotion' ending could reasonably happen in a real game after the Black Rook had captured on d8. But it would be extremely rare.
Bruce Zimov created this interesting game back in 1972. I only became aware of it today through Peter's comment. I believe Mr. Zimov's game deserves a pre-set, so I just made one. It is located at this link. The pre-set has a link to the rules. http://play.chessvariants.org/pbm/play.php?game%3DKnightmate%26settings%3DJPG-km
Note that there has just been released a WinBoard compatible version of the variant-capable engine Dabbaba of Jens Baek Nielsen. One of the games it knows is Knightmate. You can currently watch it play a Knightmate match live against my own engine Fairy-Max, on my Chess-Live! webserver http://80.100.28.169/gothic/knightmate.html for the next one or two days. If anyone knows any other WinBoard engines that can play Knightmate, let me know; then I could hold a tournament.
My small live tourney has led to a proliferation of WinBoard-compatible Knightmate engines. We now have: JokerKM ( http://home.hccnet.nl/h.g.muller/jokerKM.exe) CCCP-Knightmate ( http://www.marittima.pl/cccp) Fairy-Max ( http://home.hccnet.nl/h.g.muller/dwnldpage.html, do not forget to download the accompanying fmax.ini with game definitions!) Dabbaba ( http://homepages.tesco.net/henry.ablett/jims.html) JokerKM is the strongest, CCCP and Fairy-Max are both about 400 Elo points weaker. Dabbaba is a rebuild of an old DOS engine from the 90s, and is some 300 Elo points behind that.
The number of WinBoard-compatible engines that can pay Knightmate now has risen to 10: JokerKM 1.1.14 Lime KM 62 Faile KM 1.4.4 CCCP Knightmate Fairy-Max 4.8v Dababba 2.62g Gerbil-KM 2.0 MSKCP VanillaChess KM 1.4.4 Fimbulwinter KM 5.00 High time to hold another computer tournament. I therefore started 'The Knightmate Challenge 2010'. The games can be watched live on the web page: http://80.100.28.169/gothic/battle.html
The FIDE army is stronger. I know for sure that Commoners are weaker than Knights in a FIDE context. The Royal Knight also seems weaker than a normal King: it is very vulnerable to being chased over the board by a Queen, and subsequently mated, and it is not able to defend its own Pawn shield like a King does. It is difficult to quantify this, however. I tried to play the two armies against each other with Fairy-Max, but it crashes very often because of mutual perpetual check. (This is something Fairy-Max cannot handle, as it extends checks always by 1 ply, so mutual perpetuals leed to infinitely deep search. This is already a problem in games like Xiangqi, where the Cannons allow you to set up mutual perpetuals. But when the two Kings move differently, this becomes really frequent. The Kings just have to approach each other, and bang...! They start to attack each other directly.)
This table of piece values states that the endgame value of a COMMONER is halfway between a Knight and a Rook in FIDE Chess. Betza once pointed out that replacing the White Knights with Commoners in the initial setup can lead to a difficult game, while replacing the White Bishops with Commoners allows the White pieces to develop more quickly.
Ralph Betza also says on this web page: 'Surprisingly enough, a Commoner (a piece that moves like a King but doesn't have to worry about check) is very weak in the opening, reasonably good in the middlegame, and wins outright against a Knight or Bishop in the endgame. (There are no Commoners in FIDE chess, but the value of the Commoner is some guide to the value of the King).'
My [2006-01-10] comment here shows that Royal Knight and Commoner can sometimes checkmate a Royal Knight. This example also works with FIDE Knight and King against a Royal Knight.
Indeed. So those dreaming up the table, as well as Betza, were wrong... Set up any symmetric position with Kings + 3-6 Pawns on either side, and add one or two Commoners for one side, and one or to Knights for the other, in mirror-imaged positions, and then take any strong Knightmate engine to play out the game a few hundred times. If you can find any position where the Commoners would have the upper hand, I would be interested to see it. Give the other side two Bishops in stead of two Knights, and the Commoners are completely crushed...
25 comments displayed
Permalink to the exact comments currently displayed.