Chess: To Sacrifice or Not to Sacrifice?

First let's define "what is a sacrifice". A sacrifice is a move giving up a piece in the hopes of gaining tactical or positional compensation in other forms. A sacrifice could also be a deliberate exchange of a chess piece of higher value for an opponent's piece of lower value.

Any chess piece except the king can be sacrificed. Because players usually try to hold onto their own pieces, offering a sacrifice can come as an unpleasant surprise to one's opponent, putting him off balance and causing much precious time to be wasted trying to calculate whether the sacrifice is sound or not and whether to accept it.

While players of any level should take advantage of this strategy, beginners should use extreme caution since it can throw a game to your opponent's advantage very easily.

In the opening, never sacrifice a piece without a very good reason. Reasons can include: 

1. Gaining control of the center
2. Advancing in development
3. Build up a strong attack
4. Prevent your opponent from castling
5. Etc . . .

Here you can see that white intends to sacrifices his bishop by taking white's king rook pawn and putting black in check. White hopes that when and if, the black king takes the bishop it will expose the black king to immediate further attacks. Once black takes the bishop, white can move in for an attack with the knight and the queen.