Purdy’s Thinking System

This blog has been around for a while, so I will begin promoting older posts to the front page every once in a while, for the benefit of new readers.

In Search for Chess Perfection CJS Purdy details his ‘System’ for for evaluating a position and picking a candidate move.

I. My turn to move

1. What are all the moves I have to consider?

If there is a commonsense move you may be able to choose it without following the rest of the system. For each move ask, “What could he do if I did this?” looking for combination motifs from the other side.

2. How has his last move changed the position? What are his threats? What are his objectives?

Part one of this questions allows you to bring your reconnaissance up to date. Part two asks you to look for checks, captures and threats. If you see a threat, your first reaction should not be to search for a defense to it, but rather for a way of ignoring it

3. Complete your reconnaissance if not already done:

a. material (two bishops, bishops of opposite colors, pawn majorities);

b. king positions (exposed, lack of flight squares);

c. weaknesses (weak pawns [double, isolated, backward], weak squares, confined pieces, cramped game, overworked pieces);

d. strengths (greater space, greater mobility, well posted pieces, command of central squares, domination of open lines and diagonals);

e. development (count the # of moves needed by each army to complete its development. Credit 1 tempo to the player whose turn it is to move.) ;

f. Where could either side breakthrough?

You should be able to tell which side is better using the following descriptors: ∞ unclear, = even (0.0-0.29) , +/- white is slightly better (.30-.60), += white has a moderate advantage (.61-1.40), +/- white has a decisive advantage +- (1.41 or >).

4. Have I a good combination?

look for possible combination motifs if 3 of the following exist in the position:

1. Loose pieces, 2. Pieces that can be easily attacked by an enemy piece of less value, 3. Discovered attack, 4. Weak back rank, 5. Pinned or “skewerable” pieces along the same rank, file or diagonal, 6. overworked pieces, 7. lack of development (overwhelming force), 8. Unsafe King, 9. Open enemy lines, 10. Pawns nearing promotion. (Heisman)

Combinational Motifs:

a. geometrical;
b. nets;
c. jump moves;
d. zugzwang (endgame motif);
e. stalemate (endgame motif).

5. If not satisfied that the answer to (4) is yes, what is my best plan?

Use the reconnaissance to answer this question. How can I best exploit his weaknesses and establish my strengths, etc.

Now return to 1

II. I am considering a certain move

1. Visualize the move as though made, firmly.
2. does it leave my vulnerable to any combination.

III. It is his move

1. Reconnaissance
2. Visualize