For the typical Patzer, a knight is a knight and a bishop a bishop, they’re worth three points, and trading a knight for bishop is pretty much always an equal exchange.
While a knight and bishop are nominally worth three points, they actually become more or less valuable depending on their position on the board and the overall board layout. The next time you have a chance to exchange minor pieces to accomplish some goal, take the entire board into account when making your decision. Here are some elements to watch out for when valuing your minor pieces:
1. Knights become more valuable as they make their way toward the center and up the board. A knight on the back row is virtually worthless (“A Knight on the Rim is Dim”), because it can only attack a few squares. A knight in the center can attack up to eight squares. As a knight makes its way to the 5th and 6th ranks, it becomes a real thorn in the opponent’s side. If a knight is approaching your back ranks, look to trade one of your minor pieces to eliminate it, or chase it off with a pawn.
2. Knights on outposts can be devastating. Look for outposts (squares on the 5th or 6th rank that are protected from enemy pawns or other pieces) to plant your knights on. From a protected outpost, a knight can really hinder your opponent’s development.
3. Knights are more valuable in closed games, bishops in open games. If you are in a closed game, with the center locked up by many pawns, hold on to your knights if appropriate, and avoid knight-for-bishop exchanges. Knights can leap over the clutter in the center of the board, where they are relatively more mobile than bishops, queens, and rooks. On the other hand, in an open game bishops can fly up and down the board unhindered.
4. In the same way, knights are more valuable earlier in the game, when the board is cluttered with material, and bishops become more valuable toward the endgame, as material is removed from the board.
5. The bishop’s main weakness is its inability to attack pieces on a color other than its own. That is why it is valuable to maintain a “bishop pair” if at all possible – a white and a colored bishop that can work in tandem to attack all squares on the board. This is especially true if your opponent does not have a bishop pair.
6. Finally, a bishop that is trapped behind its own pawns (especially when the center pawns prevent it from moving along the long diagonals) is called a “bad bishop.” Look to exchange this bishop for another minor piece, move the pawns, or work to get the bishop outside of the pawn chain, so it is at least active.
Keeping these tenets in mind can help any patzer make smarter decisions about exchanging the minor pieces.