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The Insufficient Mating Material Rule

The FIDE Laws of Chess says in article 9.6:
"The game is drawn when a position is reached from which a checkmate cannot occur by any possible series of legal moves, even with the most unskilled play. This immediately ends the game."

This is a very interesting rule, it can determine the result of a game in some situations.

We all know, players agree in draw when they can't mate each other, or often earlier.

This rule says the game is drawn immediately if there is no way to end the game in mate. This is more complex than we think.
In time controlled games it is possible, that if the drawn position is not recognized, one of the players runs out of time and loses the game by time forfeit. Remember, the game is drawn, but the draw is not recognized.

This page is dedicated to summarize which situations are drawn and tries to help how to recognize them. You'll also find examples for all the cases.

See the following list and go through it up to the bottom to check which point matches the current setup.

Case One side Other side Example Result
1. King King A Draw
2. King + m * Bishops
m > 0
bishops (if more) stand on the same color
King B, C Draw
3. King + Knight King D Draw
4. King + m * Bishops
m > 0
bishops (if more) stand on the same color
King + n * Bishops
n > 0
bishop (or bishops if more) stand on the same color as bishop or bishops on the other side
E Draw
5. Any combination of pieces if there is no way to avoid stalemate F, J, K Draw
6. Any combination of pieces if it is impossible to reach mate, because pieces are blocked and can not be freed, or the free pieces can't mate the opponent's king. G, H Draw
7. Any combination of pieces if there is no way to avoid one of the above situations to happen I Draw
8. In any other cases Not draw

Bellow you can find some examples for all the above cases:

Example A
This position is clearly drawn, no side can mate the other.
Example B
This position is also drawn, white can't mate black and black can't mate white. If black's king were in a corner white couldn't control all four squares in that corner with his king and his one bishop, so mate is impossible. Therefore the game is immediately drawn when a position like this occurs.
Example C
This position is also drawn, white can't mate black even with two or more bishops if his bishops move on the same color.
White could win only if he had bishops on different color squares of the board.
Of course this is a strange situation, white has promoted a pawn to a bishop instead of a queen, that would have easily won the game.
Example D
This position is also drawn, since white can't control four squares in the corner (or six squares at an edge), so can't mate black. And of course, black can't mate white.
If white had one more knight, the position would not be drawn, because mate is possible with two knights. That is known, mate can't be forced with two knights, but if black plays bad enough, or takes suicide moves (like helpmate) the mate is possible. So a king and two knights against king position is not drawn based on the insufficient material rule.
Example E
This position is drawn, no side can mate the other since all the bishops control the same color squares. The number of bishops doesn't matter if they are all on same color squares of the board. If white could take black's bishops, or black could take white's bishop, the situation would be the same, the game is would remain drawn.
If there were at least one bishop on different color, the game couldn't be terminated in draw, because mate is possible.
Example F
Black to move. This setup is drawn, because there is no way to end the game in mate. Black can't avoid white's stalemate, so the game would end in stalemate. White's last move was Qg7+. Black now would have to take the white queen to escape from check either by Kxg7, Rxg7 or Nxg7, and after that the result would be stalemate, so the game can't end in mate. This is why the game is drawn in this position according to the rule at the top of this page.
Anyway this is a good example to show how white can save a half point from a lost position. Black has massive material advantage, and could easily win the game, if white didn't move Qg7+. With this move the game is drawn, regardless how strong black is.
Example G
This example shows a setup where there is enough mating material, but mate is still impossible. Both sides are unable to free their forces, since they can't reach the opponent's pawns. All the mating pieces are blocked, only the kings could move until the end of the Time. So the game is drawn immediately when a position like this occurs.
These positions are the so called dead positions.
Example H
This example shows another valid setup, where there are lot of forces, but mate is impossible. This position is not as blocked as the previous, since white has a free bishop. The problem is, that this bishop can't reach black's forces. Mate is impossible, so the game is drawn.
Example I
White to move. This setup is also drawn immediately according to the rule after black's move. It was Ra8+. White can't move anything else, but capture the black rook by Kxa8. After Kxa8 the setup would be drawn. So, in this position it's impossible to avoid the drawn position. Therefore there is no way to end the game in either side's mate. Therefore the game is drawn right after black's Ra8+.
Example J
Black to move. This is just an example to show how important is to recognize incoming stalemate in time. This position is drawn according to the rule, right after white had moved Qg4+. There is only one move sequence in this position and it leads to stalemate. Therefore the game is drawn, since none of the players can mate each other.
If the game hadn't ended in draw as the rule says, the move sequence would be Rxg4+, Rxg4+, Qxg4+ then Nxg4, when it would be stalemate. It's impossible to avoid stalemate, so the game can't end in mate.
Therefore this position also matches the rule, so the game is immediately drawn after Qg4+.
Example K
If you think these examples are not enough live, then please see this one.
This was the setup between Friedrich Amelung and Helmersen in Tallinn in 1890.

1.Ngxf6+ Qxf6+ (if 1...exf6, the next would be 2.Ne7#)
At this point the game is drawn according to the rule in subject, because the game can not end in either side's win.

Because white has to take the queen: 2.Hxf6+, then black has to take that knight: 2...exf6
Now both kings are blocked, none of them can move, and none of them is attacked. Only the queen side pawns remain, but they will be blocked sooner or later too. Checkmate is not possible.

Thanks for the example to Pal Benyovszki. If you have the whole game, please send it in!

Some of the above examples are very strange, and probably will never occur in normal life games. But if they still occur, players must see the drawn situation and will agree in draw. At least if everything goes normal. But life is not always logical, nor humans.

In example I it's seemingly no sense to declare draw before white's Kxa8. Why it is good to anybody to declare draw after black's blunder? I'll tell you. See the game before Ra8+. This is a clear black win, no doubt. But black blunders that Ra8+, maybe he wanted to hurry, or else. Suppose, there is no rule that stops the game in this position in draw. In this case, if the game is played over the board, white simply takes that fool rook by Kxa8, and the game is drawn. But if this is a correspondence chess game, white gets a message with that stupid Ra8+, and it's his turn. He has very few time, so he is unable to use up black's blunder in time, he runs out of time. He loses the game by time forfeit. But with this rule, after black plays Ra8+, the game ends in draw immediately, independently if white has very few time left, or not.

In example J there are more moves before the game would end in stalemate, and if the position is not recognized as drawn, both players have chance to timeout, which would cause him to lose. Despite the game is drawn according to the insufficient mating material rule, but not recognized as drawn.

So if a game is declared drawn according to the rule at least one halfmove before a stalemate (example F, I or J) or a dead position, it prevents the players from timeout. And this can change the result of the game.

Written by Andras Galos in Aug 12, 2003, with the essential help of the great people of the newsgroup.
Any comments are welcome via the Contact page.

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Chess Tournaments

Modern chess tournaments began in the 1840s and the first international tournament was held in London, in 1851. Strong international tournaments were still quite rare and in the 1880s a master would have been lucky to be able to play in one reasonably strong tournament a year.

By the 1890s, however, a master could enter many strong tournaments throughout the year, and the prize money offered at tournaments made it possible for masters to have a professional chess career.

Nowadays there are many strong tournaments for masters and grandmasters, but there are also a huge number of tournaments for players of every strength. Weaker players today have the chance of improving their play by taking part in such tournaments, which are very competitive.
Strict mode

Saying the truth, mis-writing a move in correspondence chess can be fatal for the game.
But it depends, if the miswritten move is still valid or not fully valid. For example if the check mark (+) is missing, our opponent can reject the move, and can send it back to us for correction.
But if we have two knights, one can move to e4 and the other one can move to e5, mis-writing 12.Ne4 to 12.Ne5 can be fatal, and there is no way to proof we wanted to move the other knight.
This is a problem, that can be solved in server based correspondence chess, that this club offers.
By default the server is very indulgent in accepting moves, it accepts invalid moves if they are still unambiguous, adds check and capture marks, doesn't require the move number, etc. This is for reducing the number of rejected moves, but it results that some miswritten moves are not rejected, and are accepted as a different move.
Those players who manually compose their move messages, and therefore sometimes miswrite their moves may find the StrictMode setting useful.
If they turn it on, the server will accept only fully valid, complete moves exactly as shown in the next example:
Move 1234 12.Nd2-e4
In strict mode the server requires the move number, one dot as white and three dots as black, the piece letter (even at pawns), the from square, the capture mark or hyphen, the target square, and the check mark if needed. If any of these parts is missing, or the whole move is invalid the server rejects the move.
This way the chance that a miswritten move can be valid as an other move is lowered quite dramatically.
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