Where did that come from?

Usually a chess game happens to me. Combinations most of the time come out of the blue. Now I start to learn how to combine, wouldn't it be nice to be able to concoct a combination from the beginning?
To that end I started to analyze a game behind a CT problem. Is there a sudden outburst of tactical elements, or do they gradually build up during the game?

White to move.
You can find the solution here.

Allthough the combination is pretty clean and crisp, it is not so easy to find. Yet it is all very logical.
I identified the following tactical elements that played a role in the combination (in random order):

• Knight fork Ne8
• Overworked rook Rf8
• Weak backrank
• Battery Bb3, Qc4
• Weak diagonal
• Occupation of open d-file
• Invasion with Nd6
• Qc7 and Ra8 at a knights jump distance
• The clumsy Ne7 which prevent Bf6 from defending d8

Play through the game and look at the comments.

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You see that the combination starts to build up from as early as move 9, while it is launched at move 23. In the right order:

• 9. ... f5 {At this moment the diagonal a2 - g8 is weakened}
• 10. dxe5 {After the pawn exchange the d-file is half open}
• 10. ... dxe5 {After the pawn exchange the d-file is open}
• 11. Bc4 {Occuppying the diagonal with tempo}
• 13. ... Ne7 {Putting the knight in a position where it becomes clumsy.}
• 14. ... c6 {Weakens d6. Gives white the opportunity to pressurize the d-file. Leads to overload of Rf8. Furthermore it frustrates the development of Bc8, which makes the backrank weak since the rooks cannot connect}
• 16. Rad1 {Occupying the d-file}
• 16. ... Qc7 {Putting the Queen on a knight’s jump distance to the rook}
• 18. ... Nxg5 {Gives the white knight the opportunity to occupy d6 with tempo}
• 20. ... Kg7 {Binding the king to the defence of f7, which is at knightforks distance from Qc7}
• 22. Qc4 {Putting the front end of the battery in place} a6 {Gives the opportunity to launch the combination}

The combination was made possible by 4 moves of white and by 7 moves of black. Plus something black did not do: connecting the rooks by leaving Bc8 on the back rank. The moves of white are sound moves which can be played solely based on positional considerations. Black on the other hand made some strange moves like the cramping Ne7, grabbing a pawn while having trouble with the development of Bc8, playing e4 prematurely, allowing an outpost on d6, forget to develop, forget to occupy an open file, forget to occupy an open diagonal. None of the moves of black were forced. He played them because he didn't see the consequences.

As a consequence we can conclude what you have to do in order to win the brilliancy price:

• Make sound moves based on simple positional considerations.
• Have a keen eye for the consequences of the moves of your opponent.