Practical Endings, Doubled Pawns and Tablebases (2)

Part II: With a Queen

The arrival of chess tablebases has had an especially big impact on our understanding of Queen and Pawn endings. Much more than any other type of ending, we have discovered things that are at first sight counter-intuitive. Consider the following position:

White has two healthy pawns and a very safe King position. One would think that converting White’s advantage is just a question of technique, but infact this is not the case.

The tablebases tell us that when White has the h and g pawns (or a and b pawns, allowing for board symmetry) the correct outcome -with reasonable play – is a draw!

Move the whole position one file to the left and White wins. Always. Tablebases are useful for finding exceptions to the rule. The above position is one such exception.

(As an aside, I actually had this ending (with colors reversed) in 2014 against a strong Spanish master and I managed to win it! It took a long time and was not nearly as easy as I would have expected, but I did win it. Imagine my surprise when I returned home and checked the tablebases!  It turns out that because of the peculiar geometry of the 8X8 board, especially along the edge, an incredible stalemate is available to the defender that does not exist when the pawns are on other files!)

Let us now consider the general case with both sides having a Queen instead of a Rook. One side has two extra doubled pawns, and the defender’s King is on the Queening square, or close to it (Position 2).

Every club player knows that when White has only 1 pawn extra and the defending King can blockade it (Position 1), then the result is a dead draw (barring a miracle from one’s opponent!).

Now double that useless pawn (Position 2) and all of a sudden everything changes! Instead of drawing, the stronger side now invariably is able to force a win…

To be precise, the stronger side should always win, even against perfect play by the opponent, whenever the double pawns are along the c,d,e and f files (providing, of course, a perpetual check is not available in the initial position or the pawns are too far advanced and vulnerable to attack)

The exceptions (there seem to always be exceptions in chess!) occur when the doubled pawns are along the Knight files (b and g) and, naturally, the Rook files (a and h)

The general winning plan is not very complicated, though it might very well be time consuming. The idea is simplicity itself: advance the front pawn to the 6th rank – creating mating threats – and then exchange Queens, resulting in a (hopefully) winning King and Pawn Ending:

Putting this together in Praxis

To gain a real understanding and insight into the mutual challenges and obstacles that this ending presents to both players, I have chosen the endgame that arose in the game Reshevsky vs Geller, Sousse Izt 1967, after 50 moves of play.

(I use the RPB plugin here because of the length of the game; just click on any move and a floating diagram will appear. As well, you can download the PGN from the diagrams.)

  gm Reshevsky,S — gm Geller,S
Sousse Izt 1967

This game is important to help understand the plans, techniques and methods of both sides of play.  Especially, it is clear from the analysis that Black should not have lost and only erred at the very end because of time trouble.

Hence the general case of when the doubled pawns are on the g-file (or b-file) is solved: it should be a draw with correct play.

But this example also reveals the reason why the stronger side should win when the pawns are on the central files (c,d,e and f).

What do I mean?

Let’s go back to the critical drawing position had Geller found 69…Qa4+! 70.g4 Qe8! 71.Qf5+ Kg7 72.Qf6+ Kg8. I asked the reader to remember this position:

Fine! Now let’s move this position one file to the left (the pawns on the f-file) and see what revealing props up:

Here White has 73.Qh6+! which forces the exchange of Queens and wins handily! This side check is always available when dealing with pawns on the c,d,e and f files. All White needed was a little elbow room on the right side of the board!

This ends my short exploration of the theme of doubled pawns in the centre. In the most general case, the stronger side has only practical winning chances when there are Rooks on the board; with Queens the stronger side should win more often than not regardless of how well his opponent defends.