The Dreaded Discovered Attack
A discovered attack is a very common, and often very strong, combinative strike based on one piece getting out of the way and allowing a connection to occur that, ideally, leads to a decisive gain in material. Here's a very basic example:
This worked due to the fact that the “middleman Bishop” was able to sacrifice itself with check (thus leaving white’s Queen hanging out to dry), and also to the hugely important detail that white’s Queen was undefended.
Sounds great, doesn’t it? However, if we add a pair of Bishops (a White Bishop on h3 and a Black Bishop on e7) then the sacrifice would be insane, or an admission that the player with the Black pieces is a masochist.
As you can see, two of the most important “details” in a successful combination are a vulnerable King and/or an undefended piece. In our first position (repeated in the diagram) we saw both in play: The check on g2 made use of the fact that all other things come to a standstill when one’s King is in check, which left us with the decisive fact that white’s Queen was completely undefended. But defend the white Queen and suddenly we’re facing a different kind of ballgame.
Once these basic forms of Discovered Attack are mastered, you can make use of the theme in far more complex forms:
Other than the usual combinative duo of vulnerable King and undefended piece, another key to a winning combo is simply having a weaker piece go after a stronger one. In the next position black’s Queen is the target, and though it’s protected by its Rook, that fact has no bearing on the result (decisive material loss for Black):
The potential connection (discovered attack) between the white Rook and black Queen was decisive in the example we just looked at. But sometimes the threat of that connection can lead to simple positional gain:
Okay, it's clear that the concept of a discovered attack is pretty simple and easy to grasp. But actually spotting it in a game is often anything but easy (as proven by the fact that the puzzles are rather difficult). Are you ready to show your “Discovered Attack IQ”? If so, it’s puzzle time!
Oh, keep one more thing in mind: any piece can initiate a discovered attack. You've been warned!