Chess Tactic 1: Double Attack (and How to Survive One)

Double attack = chess tactic where a single move threatens multiple enemy pieces at once 

In the image above, black plays the move Nd3. The knight attacks the queen and a rook, while clearing the way for the black queen to attack the white knight.

In case you were asking why I didn’t put an arrow that points to the pawn on a2, it’s because that single knight move that we discussed didn’t do anything for the attack of that piece. But yes, that involves another double attack, where the black queen is targeting both the h5 knight and the a2 pawn.

Kinds:

1. Fork - a single piece threatens multiple enemy pieces

Above, there are two fork situations. The black knight forks the white queen and the c1 rook. The black queen forks the knight and the a2 pawn.

2. Discovered double attack – a piece threatens one or more enemy pieces, while moving away to expose another piece behind it that attacks another enemy piece

Takeaways: 
- Even if there was only one piece that the knight attacked, this is still a discovered double attack.

- If the knight moved to a place where it wouldn’t attack any piece, this is still called a discovered attack, but not a discovered double attack.

•       Do not strictly categorize the chess tactics. Tactics cross each other and are really tangled. Just focus how to identify and apply them.

•      The double attack tactic is very effective, since in chess, only one piece can escape at a time. When you create a double attack, many times you are guaranteed to capture at least one of the opponent’s pieces that you attacked.

•      Note that pawns, knights and bishops can’t fork pieces that are of different colored squares.

•      Not every double attack is going to win material.

•      Most of good double attacks

ex: aim at unprotected pieces.

ex: aim at pieces that are supported but have higher value than the attacker.

ex: aim at an unprotected piece and a piece of higher value than the attacker.

ex: gain tempo, or improve the general position.

How to Know if You Can Survive a Fork (similarly for a discovered double attack)

Here are possible ways to survive it. And if you do not find a way, no one will.

1. There is no immediate threat if both of your pieces are protected and have less worth than the opponent’s piece that double attacks.

The black queen is forking white’s protected bishop and protected knight. However, black would have a material disadvantage if white exchanges its queen for either pieces, since a queen is worth more than either a bishop or a knight. So, white is fine.

2. Determine if one of your forked pieces can capture one of your opponent’s pieces which is of equal or higher worth.

The black queen is forking white’s unprotected knight and unprotected bishop. What white should do here is to play Nxd6, capturing black’s knight while escaping one of its forked pieces. Black can only take-back either the white knight that is now on d6, or the white bishop on e3, while one of those escapes.  

3. Determine if one of your forked pieces can attack an opponent’s piece of equal or higher worth.

Black is forking white’s unprotected knight and unprotected bishop. White should play Bf4+, escaping its black bishop while checking black’s king. When the king is checked, the king is obliged to move away from check, capture the piece that checks, or block the path of the check with one of its pieces (if it could not, it loses, and the game is over by checkmate). In this situation, it is best for black to move its king away. After black moving its king away, the white knight now has time to escape the previous fork.

4. Determine if you can escape one of your forked pieces by supporting your other forked piece. (This should do, if the opponent piece that forks yours is of equal or higher worth).

Black is forking white’s unprotected knight and bishop. White should play Be7, escaping the bishop while protecting the other forked piece.

5. Use another piece of yours that protects both forked pieces. (This should do, if the opponent piece that forks yours is of equal or higher worth).

Black is forking white’s unprotected knight and unprotected bishop. White should play Kf3 or Kf4, using the king to protect both forked pieces.

6. If one of the two of your forked pieces supports the other forked piece,
6.1 escape that protector to a place where it still protects the other piece,

Black is forking white’s unprotected bishop, and protected knight that is protected by the attacked bishop. White should play Bd2, escaping the attack, while continuing to protect the knight. Bc1 would seemingly do the same, however it allows the black queen to fork the bishop and the king with Qc3 on the next move.

6.2 or support that protector.

Black is forking white’s unprotected bishop, and protected knight that is protected by the attacked bishop. White should play Kf2 or Ke2 to protect the bishop that protects the knight.

7. Make an in-between move that makes any of the above previous ways to happen.  

Black is forking white’s unprotected knight and unprotected bishop. White should play Re2+, checking black’s king first. Later, white can escape the bishop to e6 (which is now a square protected by the rook), and protect the knight.

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