2. Discovered Check
In the first part of this series, you saw the tactical use of checks. We now take up a type of special check known as discovered check which is a much more potent weapon than simple checks.
In simple checks, you just attack the opponent’s King with a piece or pawn. In discovered check, you not only attack the King but possibly (though not always) another piece or pawn of your opponent. Even when the latter part is absent, you can gain some advantage of space or position if planned carefully.
To create a discovered check, you must have the opponent’s King in the line of attack of one of your pieces, but there is no check as yet (or we may say that the check is ‘hidden’) because another of your pieces or pawns (which by itself is not attacking the King) is standing between the King and your attacking piece. If you now move the interposing piece or pawn from the line of attack, the hidden attack is exposed or ‘discovered’ and the King will be under a ‘discovered check’.
Note: There is a sole exception to this pattern as you will see in next lesson.
The following diagram explains the mechanism of discovered check.
The Black King is in the line of attack of the White Bishop but not in check because of the interposing White Rook. If White now moves his Rook, the Black King will be under a ‘discovered’ check of the White Bishop.
You can see that the discovered check will arise irrespective of where the White Rook is moved. The power of the check comes from your freedom of placing your Rook at a position where you can reap the maximum benefit from this check, while the opponent is busy in defending his King.
In the above diagram, a little study will make it clear that you will gain most by playing 1. Rd8+. As the checking Bishop cannot be captured by Black and the Black Rook, being under Pin, cannot be moved to f7 to interpose, Black has no other alternative but to move his King to h8. Thus, the subsequent moves will go like 1. … Kh8 2. Rxf8#.
You should realize that a discovered check is not possible where the check is to be delivered by a Knight or Pawn though they may very well be in the interposing role. The check has to be by Queen, Rook or Bishop.
In certain positions where the attacked King has only one escape hole, a series of checks and discovered checks can have a devastating effect. This kind of shuttling is often referred as ‘windmilling’ or ‘see-saw’. A very famous example is shown below where White went to the extent of sacrificing his Queen to create this type of position as he was sure to recoup with interest!
| 25. | Bf6 | Qxh5 | Black had to accept the offer as otherwise he would lose his own Queen |
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| 26. | Rxg7+ | Kh8 | A normal check and Black King has only h8 square available |
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| 27. | Rxf7+ | Kg8 | A discovered check and the King has only g8 square available so long as the White Rook occupies the 7th rank |
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| 28. | Rg7+ | Kh8 | Back to the normal check! |
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| 29. | Rxb7+ | Kg8 | A discovered check again! |
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| 30. | Rg7+ | Kh8 | Repeats the normal check |
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| 31. | Rg5+ | Kh7 | The King gets some option at last but his Queen gets caught! |
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| 32. | Rxh5 | … | White won after another 11 moves |
You should also be aware of another special situation where a discovered check, coupled with a double check leads to a smothered mate (King being hemmed in by his own pieces when the last check is delivered). This type of situation has been coming up off and on over the last five centuries and is known as Philidor’s mate. The basic idea is shown below.
| 1. | Qd5+ | Kh8 | Simple check |
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| 2. | Nf7+ | Kg8 | Simple check preparing way to a discovered check |
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| 3. | Nh6+ | Kh8 | Discovered and double check combined |
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| 4. | Qg8+ | Rxg8 | King cannot capture because of Knight. So Rook has to capture, hemming in (‘smothering’) the King in the corner |
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| 5. | Nf7# | Smothered mate by the Knight check |
You can see more illustrations of this theme in Chess Tactics using opponent’s pieces to mate the king! and Chess Tactics: the Old but Evergreen Philidor’s position.
We take up double check in the next part.
6 Comments
[...] We will continue the discussion of the other tactics in the next part. [...]
Some time back I was told by a player that one very strong GM told him that the way you find tactics is just look at the position and try various moves until you find something that works.
Either he misunderstood the GM or he was given faulty advice. That approach may work for a GM who has a vast storehouse of patterns in his mental database, but most of us ordinary players don’t. Furthermore, not all positions contain combinations. In fact most don’t. So the problem for us ordinary players becomes one of recognizing when there MAY be a combination lurking somewhere in the position.
To ferret out these possibilities, I personally have found CJS Purdy’s advice to be the best. Purdy advised looking for the following “signposts” with the idea that if you see one or more of these things, there is a possibility that there’s a combination possible:
1. Look at all checks.
2. Undefended pieces.
3. Pins and forks.
4. Pieces (esp. the King) that do not have any “escape” squares.
5. Masked pieces (i.e. pieces on the same line)
6. Pieces that may be performing more than one defensive task
7. Briefly look at bizarre and surprising moves, sacrifices, Pawn breaks, “obviously unplayable” moves.
As Purdy points out you need to perform this search twice every move. After your opponent moves and before you move (to make sure you aren’t setting up any of the above situations for you opponent to utilize!) Of course if there’s no combination available, you have to find another reasonable move which means you have to be versed in the art of strategy and planning…but that’s another subject.
In any case being familiar with the “elements” or motifs that are used in tactical solutions (such as you cover in this blog) are also essential.
@Tarta, thank you so very much for adding your tips. I am sure the readers will take note and make sure they apply the ideas in their games. You should read the book Imagination in Chess: How to Think Creatively and Avoid Foolish Mistakes, there are a lot of useful guides from Attila Turzo on the topic. Further Chessbase, has some great collection on the topic.
[...] borrow the first diagram from the previous lesson after a little alteration to show how double check comes about and the effect it can [...]
Yes, i will apply this in my game. Thank you for adding this great tips!
A smothered mate counts as two wins, actually