Breaking the Rules
Chess is all about rules. Each uniquely-shaped piece has its own way of moving, each player takes turns beginning with white, and so on. Basic rules aside, several principles are then emphasized, such as developing quickly in the opening, castling at some point before entering the middlegame, and avoiding doubled pawns. Then there are more complex rules-of-thumb, such as blockading passed pawns, striving to keep a good-colored bishop, while trading off the worse of the two, maintaining tension as long as possible, and trying to obtain or maintain the bishop pair against some combination of knights and bishops. Basic rules aside, the position itself should ultimately dictate the "rules", while everything else should be treated as guidelines.
In the fifth game of the World Chess Championship match in 1972, Spassky managed to get the bishop pair as well as a passed pawn against Fischer. Despite this, the position favored Fischer, whose pieces had greater prospectives for play in the actual position.
In this position, white's pawns are blockaded, making it difficult for white to push forth with his passed pawn, as well as take advantage of the scope of his bishops.
Black, on the other hand, has a kingside pawn majority and has the only knight on the board, which has good maneuverability despite the blockade of pawns.
Fischer ultimately prevailed with dual threats on the kingside and queenside:
In a recent game, I myself was guilty of making this kind of conceptual blunder. I was a pawn up with a superb bishop against a "bad" one, and I refused to trade the excellent bishop for what I believed at the time to be a pathetic knight.
In spite of my hesitation, the position screamed for such an exchange: the defenses around black's king were guaranteed to be busted open, while white would have good attacking chances with a rooklift that came with tempo.
Instead of carrying out such a plan (credit for those ideas, by the way, go to erikido23 and NimzoIndianDefense), I ended up playing poor moves and responding to "threats", allowing black to ultimately better his bishop and blockade mine and win the game.
The entire game was as follows:
With these examples, I hope to show that general guidelines and principles may contradict each other at times. The key to success is to pay attention to the position itself, and go by a plan; without one, even a clearly winning position may be lost, or perhaps may reveal itself to be not as "clearly winning" as one might have first believed.
