If you study chess books and there are thousands of them - you can learn to play the opening almost by rote.
Not so the middle game! Here every player must be on his own; he must use his ingenuity in analyzing situations that are always different.In the opening you merely strive to develop your pieces to good squares. In the middle game you try to gain a decisive advantage. The player will win who:
1. Has the better position; or
2. Has greater king safety; or
3. Has material superiority (loses fewer pieces than his opponent); or
4. Has greater mobility to move his pieces.
Former world champion Edward Lasker used to say, "Play for good positions, and the positions will play themselves."
Rooks: Place your rooks where they will control open files. An open file is one on which you do not have any pawns, even though you may have other pieces on it. A rook, back on your first or second rank, but commanding an open file, is like a cannon aimed to fire later.
If you can double rooks, either both on the same rank or on the same file, you have a power as great as a queen. As the game progresses, if you can lodge one or both of your rooks on your seventh rank, they may be decisive.
Knights: A knight at KB3 (Kf3) is a tower of defense. If you are a beginner, try to preserve a knight at your own KB3 (Kf6) and try to destroy your enemy's knight at his KB3 .
A knight can also be a tower of defense at K5 or Q5 or anywhere centrally advanced on the board. But only advance knights to such squares when they cannot readily be attacked there by pawns.
Bishops: Place bishops where they control long diagonals, not short ones. Above all, place them at commanding diagonals pointing at the enemy king position, even though the king may be well protected at the moment.
If you can establish both your bishops back on long diagonals pointing at the enemy king, they are like cannons aimed to be fired later, as rooks are on open files.
Pawn structure: This is defined as the relation of your pawns to each other. To visualize your pawn structure, picture in your mind how the board would look with all your pieces removed except your pawns - would they support each other?
Avoid doubled pawns - two pawns on the same file. Doubled pawns slow each other down. Early in the game, doubled pawns are not too bad, but later they will hinder you.
Avoid isolated pawns - a pawn with no other pawns close to it. The best protection for a pawn, especially an advanced pawn, is a companion pawn on the next file to it.
Avoid retarded pawns - a pawn left far behind the general advance. It is too easily picked off by your opponent.
In the middle game, as in the opening, avoid unnecessary pawn moves. Play with the major pieces, not your pawns.
Reinforce key center squares. In the middle game you are still battling to control the center of the board. Protect each of your pieces on the crucial center squares by two or more other pieces, so that if one protector is captured, others remain to buttress the center.
Do not try to break through the center unless you count your pieces there. If a mental count shows that you have more pieces concentrated on the center squares than your opponent, then maybe you can exchange pieces and crash through to disorganize his rear defenses.
Avoid exposing your king while queens and other strong pieces are still on the board. And the converse rule is, aim to shatter the enemy king's protection and expose him.
Keep your king in a corner behind a screen of pawns and other pieces. But take care that your king is not trapped behind his cover.
To expose the enemy king it is sometimes worth sacrificing.
It is still dangerous, even in the middle game, to move your queen far out on the board, unless you see a good chance for attack. The queen that forays out too early to pick off the enemy pawns in the board's corners is often trapped there.
It is wise to keep the queen a little distance from your king, lest she be "pinned" against the king. If your opponent puts a rook on the same file as your queen or a bishop on the same diagonal as your queen, better move her - even though other pieces are in between, they may suddenly be moved and leave your queen exposed.
DESERET NEWS PROBLEM 2,948
Sept. 2, 1994i
White to move and mate in two.
Solution to Problem No. 2,947: 1. Q-R5 (Qh5).
Congratulations to the solvers!