You can always win material or get a checkmate if your opponent overlooks your threat. But there are some threats your opponent cannot get out of, even if they notice them.

  Problems can be solved because either you have:

Double attack

or

Concentration of force against a fixed point

(When I say a fixed point I mean either a piece than has limited mobility, like a King or a Pawn that can't run away. Another immobile point is a pinned piece.)

  Most junior games are decided by tactical threats, traps and oversights. If you get better at tactics your results are bound to improve.

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A. Winning material by concentration of force against a fixed point

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based on Alekhin-Nimzovitch, 1930

White has four pieces attacking c6, and Black defends the Knight with only three. Black will lose material because none of the four basic defences work:

A Avoid - the Knight is pinned to the Queen and cannot avoid the attack

B Block - Black cannot block the attack by putting a Pawn in the way

C Capture - Black cannot capture any of the attacking pieces

D Defend - Black cannot defend the Knight with any more pieces

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A. Winning material by double attack

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Christiansen - Karpov,1993

White's Queen on d1 has just moved back from c2, attacking two points at once - d6 and h5. Black cannot defend both and so must lose material.

  So, these are the two basic principles.

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B. All problems can be solved when you hit on the idea.

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Try this one: Black to move and win.

Black to move.

  What is the idea in this position? What do you notice about this position?

  1. The White Knight on h4 is attacked once and defended once. If we attack it again it will need to move or be defended because we have a 2:1 greater concentration of force

  2. The White Rook on f1 is undefended.

  3. The White King and Queen are safe, and the White Pawns can probably be defended.

  4. Is there any idea here? If we attack both the Rook and the Knight with one move, this might create a problem for White. Is there any move which attacks f1 and h4? Yes there is!

  5. 1...Qc4! With a double attack on f1 and h4.

  6. What can White do? White needs a defence which either defends both pieces at once or somehow creates a counterattack. No such move is there. Solved!

  When you solve a problem you usually know it straight away - it's like solving a sum. The only warning is: problems in books always have a solution - but real games might not have!

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A. Make good things happen: examine moves that smite!

We don't know how the last position above came about, but it looks like White was careless and Black just took the chance that was there. But you sometimes have to make good things happen. You have to force your opponent to do what you want. You can do this in two ways

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Playing a check: everything stops for a check!
Playing a capture: if your opponent does not recapture you will win material

Purdy talks about "smiting" moves - checks and captures. In fact, the best move is a move which is a capture with check!

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D1: Winning material by playing a forcing check
White to play and win:

White to move

  What's the idea here?

  1. The Black King has no moves - it's very nearly mate! But Black is covering h7 and g7. I have a check on h4 or h5 with the Queen, but that doesn't do much: my Queen and Rook can do nothing more by themselves.

  2. I would like to get the Bishop into play - for example on the long diagonal a1-h1. In fact, at the moment, if only I had some support for c3, I could play Bc3 winning the Queen by a deadly pin!

  3. Is there any way I can cover c3? Yes there is: I can cover it by a Queen on g3.

  4. If I just play Qg3 Black may have time to get out of it - I must not give my opponent any choice! I must play forcing moves - like checks...

5. Aha! 1. Qh4+ Kg8 2. Qg3+ Kh8 gets my Queen to g3 without Black being able to do anything. I can now play 3. Bc3, winning - Solved!

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D2: Winning material by playing a forcing capture
Black to play and win:

1. One idea: if the Black Queen on e2 was a Black Knight - I'd win the White Queen by double attack (knight fork) And even better - I can move a Knight on f4 to e2!

  2. BUT if I move the Queen away quietly White can move the Queen, or even take the Knight with the one on d3.

  3. So I can't move the Queen away quietly: I must move it noisily - forcingly - I must smite my opponent!

  4. I can play Queen takes the Rook on f1 with check. This must be the most forcing move! - but after Kxf1 I have no fork on e2.

  5. I can play Queen takes Knight on f3: if White takes the Queen I play ...Ne2+ and ...Nxd4, coming out a piece ahead. If White doesn't recapture, I'm still a piece up. Solved!