To chessify Jane Austen, it is a truth universally acknowledged that all chess players in possession of a weak square are doomed to a miserable existence. The concept of weak squares appears rather straightforward: avoid creating them, but never fail to utilize them. In fact, most positional manuals eschew the topic altogether. While the subtleties of maneuvering or the benefits of positional sacrifice obviously require elucidation, no positional training is required to identify the cause of Black's troubles in the following position:
You guessed it: the f5 square is horribly weak, and after the imminent Nf5, White will simply tear Black's position apart. True, the square is "protected" by my light-squared bishop, but after 1...Bg5 2.Nf5 Bxf5 3.exf5 Black found little relief! I was tempted to resign immediately, but did so only after 12 more moves of agony.
However, modern grandmasters thrive not only because they have mastered the principles of positional chess (a task that might have appeared daunting 200 years ago), but because they know precisely when and how to deviate from these principles. While an amateur may well understand the rationale behind developing a bishop before a knight or temporarily positioning a knight on the side of the board, he or she might find it difficult to explain how strong players break apparently inviolable positional rules with impunity. Each article will hopefully come one step closer to resolving this conundrum, and as you may have guessed, today's sub-topic is a particularly thorny one: when is it permissible to voluntarily weaken a square?
I always write under the assumption that every strong move or subtle idea can be logically and clearly explained. Most world-class players certainly possess an accurate intuition (i.e. they sense that a move is correct or incorrect without much calculation or logical reasoning), but all of their decisions can be decoded. To this end, we will introduce a concept that will streamline our quest for an answer to the aforementioned question: inaccessibility.
Put simply, inaccessibility refers to the idea that a square can often be permanently weakened if your opponent cannot immediately access it with a desirable piece. From a psychological standpoint, it is often quite difficult to leave a square terminally weak, but concrete thinking trumps general evaluation nine times out of ten: if a square is inaccessible, do not be afraid to weaken it! The following game is a terrific illustration.
So what should White do? Well, of course there is 27.f4, nipping the idea of ...e5 in the bud, but no self-respecting player would ever make such a positionally heinous move on the board...or so you might think! Let us enumerate the flaws of 27.f4. Of course, the bishop will be closed in by his own pawns, but it can later reroute to the a5-d8 diagonal with Be1. Most importantly, however, 27.f4 leaves the e4 square horribly weak. If Black can position a knight on e4, the tables will instantly turn to his favor. But take a closer look: to actually maneuver his knight to e4, Black needs a staggering eight moves (...Nh8-g6-e7, ...Kh8(7), ...Qf7, ...Ng8-f6-e4)! To crash through on the queenside, White needs half that time. Thus, since the e4 square is inaccessible, the preclusion of ...e6-e5 makes this trade-off incredibly favorable for White.
Unfortunately, cases of total inaccessibility are relatively rare. In fact, some may even argue that an unreachable square cannot be classified as a weakness at all. In any case, what truly distinguishes leading chess players is their ability to weaken a square that can be accessed, at least to some extent, by the opponent. Chess is a quid-pro-quo game at its heart, and you must be cognizant of the fact that to dent your opponent's solid position -- to introduce a defect that you will later seek to utilize -- frequently requires a major positional concession from your side. Sargissian-Tomashevsky was an exception, but in the following game, Bobby Fischer shows us that even ostensibly ludicrous positional blunders should be considered!
What's so rewarding about chess is that hard work -- a headstrong desire to penetrate the thought process of a legendary chess player -- almost always results in an aha moment. For me, one of these moments was a realization that the disobedience of one positional principle (e.g. do not voluntarily weaken a square) is the observance of another, no less important principle. In Fischer-Unzicker, White weakened the e5 square but totally restricted the movement of the c8 bishop in return. In the following game, Boris Spassky epitomizes the quintessential "quid-pro-quo-ness" of chess: the only way to unlock the path to Black's king is to create a gaping (and accessible) central hole.
The position arose out of a relatively tame Breyer Ruy Lopez. Black's queen seems out of place, but in fact, Black is eyeing the possibility of ...Bh6, forcing the trade of dark-squared bishops and making the weakness of g5 less noticeable. On the other hand, White's knight on h2 is terribly inactive while Black's knight is firmly situated on the dream square c5. To arrive at the correct decision, it is important to recognize just how time-sensitive this position is: given one more move -- ...Nfd7, perhaps -- Black will rid himself of any kingside dangers. For instance, 1...Nfd7 2.Be3 Qe7 (2...Bh6 is also feasible) and Black already has the edge.
Boris Spassky | Image Wikipedia
Thus, White must act before Black plugs all of his kingside holes. The best way to do so is obviously to open the position, but the only way to do that is the dreadfully weakening 1.f4. The problem with this move is rather conspicuous: after 1...exf4 2.Rxf4 Nfd7, Black's knight will entrench itself on the ideal square e5. After 3.Raf1 Ne5, for instance, White is positionally busted.
Once again, strong players have the ability to consistently penetrate the superficial layer of a position to immediately and precisely locate its latent aspects. In this case, Spassky recognized that, positional considerations aside, he had a rather formidable conglomeration of pieces on the kingside; whereas Black's rooks, c5 knight, and b7 bishop are doing little to defend the monarch. If White can open the h-file, his rook and queen will have a prime access route to the Black king. Hopefully, by this point your intuition is screaming at you to sacrifice the knight!
I would encourage you to play through this game more than once. Always remember that positional concessions -- no matter how significant -- are perfectly permissible when made for a concrete tactical gain.
By way of a summary, I would now like to present an example from modern top-level chess. It is given as an exercise, but since you know the topic of the article, it should not be very difficult to find the correct first move! In any case, try your best to apply the concepts of inaccessibility (or partial inaccessibility, as in Fischer-Unzicker) and tit-for-tat -- weakening a square to further your prospects in another aspect of the position. Then, be sure to read the annotations carefully -- the logic behind a move is often more important than the move itself! Note: After you have solved the one-move exercise, please scroll down to view the entire annotated game segment.
To be sure, chess cannot be reduced to an algorithm. You will always have to be the one making a decision, but hopefully, this article sheds some light on the various ways in which an ostensibly heinous positional blunder can be rationalized. Since it is my first "real" article, I would encourage any comments, constructive criticism or discussion. Auf wiedersehen!