Out of all the different tactics that can occur in a game of chess, the ‘fork’ is possibly the most common of them, up there with pins and skewers, that are also very common. Usually the outcome of a fork is that the player who is ‘forked’ loses material, most often an exchange – losing a rook for a knight.
In your games, if you can more quickly spot the possible forking squares then you are less likely to fall for the rookie error of letting their knight jump into that square. Alternatively you can move your pieces to different squares so that they are not able to be forked. The pattern of forking squares is illustrated below:
For a fork to occur, the knight must be simultaneously attacking 2 enemy pieces. The cases where the knight forks is when the forked enemy pieces are on both 1 and 2 or 1 and 3 or 1 and 4 etc… The total possible number of combinations is found by 8C2 = 28 (some maths). First, here are 4 examples of simple forks, in each case, the fork wins material:
In figure 2, if white plays Nf4+, black will lose his queen after being forced to move his king. White will then go on to win in standard fashion.
In figure 3, white can fork black by playing Nc7+, which wins the rook after the black king moves somewhere. The material imbalance should then be enough to simplify into a winning endgame.
In figure 4, white can play a BIG fork, that forks not 2 but 3 pieces! These types of forks are sometimes called ‘scorpions’. When white plays Nd6+, it is clear that black is in trouble.
In this position, white can fork black with Nxf7 -This wins the exchange. To give you some idea, this trap is one that has arisen out of the opening. It could have happened like this: 1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 4. Ng5 h6?? 5. Nxf7.
In my eighth league game, there was a tussle in the middlegame where my opponent was threatening a fork on numerous occasions, which I prevented, and went on to draw, which also happened to be the result of our team as a whole. I will show you these:
After my opponent played 13. N2b3, the position in figure 6 was reached. There is a very concrete threat of the fork 14. Nc5+ which is unpleasant for black, because after the black king moves somewhere and 15. Nxa6 bxa6 and black has doubled pawns, and white is now able to castle, since the light squared bishop no longer prevents 0-0. To circumvent this threat I played 13…, b6 which I still believe to be the best move, as it controls the forking square on c5, while also giving my a6 bishop some air to breathe.
They continued 14. a4! which is an active attempt to try to throw me off balance. If they play 15. a5 on their next move, I generally want to meet that with …, b5 to keep the position closed. However, after b5 I allow the knight fork on c5, so I have to first arrange some cover for the c5 square, I do this by the following: …, Nc6 (figure 7)