opposition checkmate

Originally posted by Wulebgr
Originally posted by techsouth
[b]You want the opposition to occur at the end of your opponents move.

This is the reverse of the definition of opposition. It should be at the end of your move.

If you are on f3 when he is on g5 (rook on a4), when it is your move DO NOT play Kg3. He can then play Kf5 and move all the way toward your rook ...[text shortened]... tered before illustrates all this, although I didn't actually step through it.

It does.[/b]

Originally posted by Wulebgr
Originally posted by techsouth
[b]You want the opposition to occur at the end of your opponents move.

This is the reverse of the definition of opposition. It should be at the end of your move.
[/b]

In spite of an apparant squabble about a definition of a word, this describes the mechanism I intend to describe. Perhaps I could more correctly say that you want your opponent to take the opposition. Point being that the kings are in opposition and it is your opponents turn.

More misleading advice.

Rather, keep your king on the same row as your opponent's king until he/she is on the edge of the board. Then, keep your king on the adjacent file.

While there may be other approaches that also work, I don't see how this can be characterized as misleading if it works. I haven't read the book you describe, however I am certain I can checkmate the author if I have a king and rook and he just has a king.

As I pointed out, verbal description is difficult, so perhaps a little more kindness is in order. Nevertheless, your description as written suffers a fatal flaw in that it describes nothing that forces your opponent to move to the edge. You can't wait for him to move to the edge if he is not forced somehow to do so. If you keep moving your king such that it has opposition, he can just move back and forth.

I have no doubt you can checkmate with a king and rook, but kids I have tried to teach have great difficulty mastering this. I've had the most success suggesting they make their opponent take the opposition. Also, I find it personally much easier to focus only on driving to the edge without regard to whether it also is tending toward a corner.

Originally posted by techsouth
Originally posted by Wulebgr
[b]Originally posted by techsouth
[b]You want the opposition to occur at the end of your opponents move.

This is the reverse of the definition of opposition. It should be at the end of your move.
[/b]

In spite of an apparant squabble about a definition of a word, this describes the mechanism I intend s only on driving to the edge without regard to whether it also is tending toward a corner.[/b]

I teach kids. I found your explanation of opposition a bit confused, and nothing is worse for beginners (especially kids) than confusing the lingo.

Go back to the start of the thread. Twenty minutes after the original post, I posted a complete solution. As your description of how to accomplish the task deviated in significant respects from my demonstration, I though some clarification was needed.

In the position below with black to move, white has the opposition.



If black moves back (towards the edge), white should move the king forward, maintaining the opposition: meet 1...Kc7 with 2.Kc5; meet 1...Ke7 with 2.Ke5.

If black moves to the side, the rook should be used to cut off the king:
meet 1...Kc6 with 2.Rb2; meet 1...Ke6 with 2.Rf2. Then the defending king must either take the opposition, but be subject to a check that drives it towards the edge, or it must move towards the edge (and white will maintain the opposition).


Employing the method you advocate may work, but it wastes moves. It could take 12 moves from a position that is a forced mate in 8 using your method. You advise is misleading because it is not the most efficient.

I've watched many beginners shuffle their rook back and forth across the board to get it away from the defending king when the king could move up to protect the rook instead. That's the consequence of following the advise you offered.

When I test kids on this checkmate, I set up a mate in 16 and give them 25. They can make some errors, but not many. Last week a kid tried a method similar to yours and required 27 moves. Then, I showed her, and said the things in my post, and she did it in 19 moves.

I use the method where you get the kings lined up one rank or file apart then check with rook to drive it to the edge. It works like a charm but I've heard a faster way is using the rook to square off the king and drive it to the edge. Not sure how this works. Do you just use your king to guard the rook? I can't see how this works.

Originally posted by Wulebgr
Fritz 10 does not see 20 moves in advance, except in certain forcing lines with relatively few pieces. In some endgames it can see 99 moves deep in fractions of a second, but in typical middlegame positions, it runs at 16 plys (8 moves).

If the programmers thought otherwise, perhaps they did not understand the rules regarding stalemate.

That's why I said it was pretentious; their claims were totally ludicrous.

Originally posted by Ramiri15
That's why I said it was pretentious; their claims were totally ludicrous.

That's what I thought you meant. Do you recall the name of the program?

Originally posted by deeploser
I use the method where you get the kings lined up one rank or file apart then check with rook to drive it to the edge. It works like a charm but I've heard a faster way is using the rook to square off the king and drive it to the edge. Not sure how this works. Do you just use your king to guard the rook? I can't see how this works.

When the kings have an odd number of squares between them and they are on the same rank or file, the player to move does not have the opposition. When they have one square between them, I use the rook to check and drive towards the edge. In the sequence I posted near the start of this thread that proved less effecient at one point (requiring two moves longer than Fritz deemed necessary).

Fritz's improvement might be a partial answer to your question. Also consider the position below with white on move.



White can move the rook up the c file to constrain the black king. 1.Rc5 would be too far, as the rook would need to move again. 1.Rc4, however, places the rook at the correct distance--where the white king arrives in time to protect the rook from capture.

Nevertheless, according to Fritz both Rc5 and Rc4 lead to checkmate in 15, while moving the king to d2 or e2 lead to checkmate in 14. Kd2 seizes the distant opposition.

After I posted I had that idea and went into CMX to test it. Worked very well. Kind of funny because I do almost the same thing with the queen and king but with the queen it's a little faster because of the diagonal. Faster to stalemate if you're not careful.

Originally posted by deeploser
After I posted I had that idea and went into CMX to test it. Worked very well. Kind of funny because I do almost the same thing with the queen and king but with the queen it's a little faster because of the diagonal. Faster to stalemate if you're not careful.

The most frequent error I see among beginners is frequent checks, instead of closing the cage. Check...check...check, but never checkmate.

Consequently, with the queen I forbid any check that is not mate (its not always the most effecient, but it teaches proper habits).

With the rook, check is permitted, but only when it forces the defending king one square closer to the edge.

(I practice against Fritz, still, although I learned to perform these elementary checkmates 30 years ago. It's nice to know that I can fire off eight moves in four seconds in a time scramble.))

CMX sets up random king queen king and king rook king endgames so for about a week I did them at least 3 times in a row without stalemating or draw by 3. I wished I could use it in linux.