Please turn on javascript in your browser to play chess.

#### Only Chess Forum

1. 11 Sep '12 23:16
Hi, I'm doing a little research and would be grateful if you could dedicate a few moments and answer the 4 questions below.

Each question consists of a chess position from the King + Rook + pawn vs. King + Rook ending, correct evaluation (checked with the tablebases), and several explanations why that position should end with that particular result with perfect play from both sides. These "explanations" are generated by different AI/machine learning algorithms (I'm trying to find if there is one better than the others, or even if there is any use of them at all).

Choose the option that you find most useful and comprehensible. Some of the explanations are quite lengthy, and some of them don't make much sense, so you don't have to answer all of the questions, but any kind of contribution would be appreciated. Answers should be in the form "1a, 2d, 3a", etc. You may post them in this thread or PM to me.

Meanings of some of the concepts used bellow:

(a) "Zone in front of the pawn" - all squares ahead of the White pawn in pawn's file, and in the adjusting files:

(b)"Pawn square zone" - all the squares such that if the opposing King occupies one, it can prevent the pawn from safe promotion (assuming the King can reach the promotion square without any obstacles). This zone can be found by "drawing" diagonals to NorthWest and NorthEast from the pawn until the edge of the board, and then going back vertically until the rank of the pawn, and filling the obtained rectangle. This is used in pawn endings, I'm sure you all know this rule...

(c) "Distance" between two pieces is the maximum of their rank difference and file difference, i.e., in how many King's moves one could reach another in the fastest route (assuming there are no obstacles).

Also, I'm interested in opinions of players of varying strengths, so please don't be discourage if your rating is not very high! Thank you!!

Position 1: White to move
This position is won for White because:
(a) Black Rook is under attack, and Black King is behind the pawn.
(b) Black King is not inside the zone in front of the pawn, Black King is not inside the pawn square zone, Black King is at least as close to the pawn as White King, pawn is not on the 7th rank, and Black Rook is under attack.
(c) Black King is not inside the pawn square zone, White King is at least as close to the pawn as Black King, White King has advanced past the 2nd rank, and the distance between White King and White Pawn is less than 5.
(d) Black Rook is under attack, and Black King is not inside the pawn square zone.
(e) Neither of the above is useful and comprehensible.

Position 2: White to move
This position is won for White because:
(a) Black King is on the rook's file on the same side of the board as White King, White Pawn is not the knight's, bishop's or central pawn on the same side of the board as White King, and the Kings are at most 2 files apart.
(b) White Pawn has advanced past the 5th rank, and White King is closer to the pawn by at least one move than Black King.
(c) Black King is not inside the zone in front of the pawn, Black King is not inside the pawn square zone, White King is closer to the pawn by at least one move than Black King, White King has advanced past the 2nd rank, and the pawn is not the rook's pawn on the opposite side of the board as White King.
(d) Black King is not inside the pawn square zone, White King is at least as close to the pawn as Black King, White King has advanced past the 2nd rank, and the distance between White King and White Pawn is at most 4.
(e) Neither of the above is useful and comprehensible.

Position 3: Black to move
This position is drawn, because:
(a) Black King is not inside the zone in front of the pawn, White King is at the same distance to the pawn as Black King, White Pawn is not on the 7th rank, Black King is not behind the pawn, and White King is not inside the zone in front of the pawn.
(b) White King is at the same distance to the pawn as Black King, White Pawn is not on the 7th rank, Black King is not behind the pawn, and White King is not inside the zone in front of the pawn.
(c) Black King is inside the pawn square zone, and the Kings are at most 2 ranks apart, and on the opposite sides of the board.
(d) Neither of the above is useful and comprehensible.

Position 4: Black to move
This position is drawn, because:
(a) White Pawn is on the knight's file on the opposite side of the board as White King, but not on the 7th rank.
(b) Black King is not inside the zone in front of the pawn, White King is closer to the pawn than Black King, Black King is inside the pawn square zone, and the Kings are no more than 1 file apart.
(c) White King is closer to the pawn than Black King, Black King is inside the pawn square zone, Black King and White Pawn are more than 3 files apart, White Pawn is not the knight, bishop or central pawn on the same side of the board as White King, Black King is on file a or file b, the Kings are at least two ranks apart and on the same or adjacent files, and White King has advanced past the 4th rank.
(d) Black King is inside the pawn square zone, and the Kings are on the same or adjacent files.
(e) Neither of the above is useful and comprehensible.

2. 12 Sep '12 10:05
My rating is about 1600 on RHP. I must admit that I have little experience with endgames, so my evaluation is very simplistic.

1e
2b
3b
4e
3.  Ponderable
chemist
12 Sep '12 11:03 / 1 edit
I am one of those low rated players

1c
2b
3c
4d
4. 14 Sep '12 18:05
Thanks guys.
In fairness, the positions are quite tricky. Maybe in the 3rd one you could say that Black King will get behind the pawn since White King will be checked by Black Rook from behind, I think others are not that easy to explain coherently. I'm a bit surprised no one said they are all rubbish (very much an expected outcome of the experiment...)