Invaders and helpers
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| Black to move |
1k6/1b3p1p/p7/3qp3/Np5Q/4BP2/PPP3rP/R4K2 b - - 1 26
Jean-Marc Degraeve vs. Laurent Guidarelli (2003)
Source Chessable The Checkmate Patterns Manual
- The black queen and bishop cooperate to invade f3
- Once invaded, a new invasion square emerges: The black rook and queen eye to f2
- But that focal point is defended by the white queen and bishop
- After 1. ... Qxf3+ 2. Bf2 the helper black rook sacrifices itself 2. ... Rg1+ and acts as a magnet to attract the white king to another square
- White gives mate from one of the two invasion squares g2 or h1
The invasion squares are clearly dynamic, and move with the pieces
It’s always fascinating to look at the game score [Chess Tempo] and try to determine where (and particularly WHY) the loser went wrong in the game.
ReplyDeleteDegraeve, Jean-Marc (2541) vs Guidarelli, Laurent (2392)
Date: 2003-08-19
Event: ch-FRA, Aix les Bains FRA
Round: 2
Result: 0-1
Opening: Sicilian Defense, Najdorf Variation (B90-99)
Problems: 172935
1. e4 c5 2. Nf3 d6 3. d4 Nf6 4. Nc3 cxd4 5. Nxd4 a6 6. Bc4 e6 7. O-O b5 8. Bb3 Be7 9. Qf3 Qc7 10. Qg3 Nc6 11. Nxc6 Qxc6 12. Re1 Bb7 13. Qxg7 Rg8 14. Qh6 O-O-O 15. f3 Rg6 16. Qh3 Kb8 17. Bf4 Rdg8 18. Re2 b4 19. Na4 e5 20. Be3 d5 21. exd5 Nxd5 22. Bxd5 Qxd5 23. Rf2 Bh4 24. Qxh4 Rxg2+ 25. Rxg2 Rxg2+ 26. Kf1 [the puzzle position] Qxf3+ and White resigned
After the first 12 moves, GM Stockfish evaluates the position at 0.0. On move 13, White accepts the “poisoned pawn” on g7 and the evaluation shifts in Black’s favor. Why should that be?
Black already has a Q+B battery aimed at g2 and the White King. Grabbing the g7 pawn opens the g-file and allows the BRh8 to move to the g-file with tempo. This gives Black a clear superiority on g2 at the cost of a pawn. I note that in the 18 games in the Chess Tempo database, the outcomes after 13. Qxg7 are White wins = 44.4%, Draws = 5.6%, Black wins = 50%. Both players are now playing for two results, with Black having a slight edge.
I would have thought that a 2541-rated GM would have been more cautious, but “a pawn is a pawn is a pawn,” and White IS higher rated by 149 points. Perhaps this blinded him to the fact that Black IS a GM also. GM Stockfish prefers to strengthen the e5 pawn with 13. f3, immediately attempting to blunt the long-distance effect of the Black battery and the Black initiative.
After 13. Qxg7 [-0.38] Rg8 14. Qh6 O-O-O 15. f3 Rg6 16. Qh3 Kb8 17. Bf4 Rdg8 18. Re2 b4 19. Na4 e5, the evaluation slides upward for Black with the initiative, a lead in development, centralized and coordinated pieces, and a clear target on g2. White’s pieces are NOT coordinated for defense nor toward any Black target(s), and he is forced to meekly respond to Black’s threats.
After 20. Be3 d5 21. exd5 Nxd5 22. Bxd5 Qxd5 Black begins tearing open the attacking lines to get at the White King. Notice how ineffective the remaining White pieces are: the WNa4 and WRa1 are totally useless in defense of the King. The three pieces in the vicinity of the White King [“defending” the White King] are uncoordinated for that task.
GM Stockfish points out that 23. Rd2 [-0.65] counterattacking the Black Queen would be somewhat of an improvement, and keep the third result (a draw) within reach. 23. Rf2 attempts to “defend” both g2 and f3, thereby overloading the Rf2.
Black at this point had to “SEE” the weaknesses and the scenarios associated with those weaknesses. He begins his combination by directly attacking the overloaded Rook with 23… Bh4. This is a duplo move, because it also tempts the White Queen to capture it, thereby removing its protection from the critical g2 and f3 squares. 24. Qxh4 [-5.76] loses by force. GM Stockfish recommends 24. Rd2 [-1.63], again counterattacking and attempting to blunt Black’s attack. White could only wish that Black would be satisfied with gaining material.
24… Rxg2+ 25. Rxg2 Rxg2+ [+6.09] launches the direct attack on the White King. Capturing the Black Rook on g2 leads to mate in 2: 26. Kxg2 Qxf3+ 27. Kg1 Qg2#. White played 26. Kf1 {the position given in this blog post} and Black executes the White King with 26… Qxf3+; White resigned. Either 27. Bf2 Rg1+ 28. Kxg1 Qg2# or 27. Qf2 Rg1+ 28. Kxg1 Qh1 ends the game. The Black move 27… Rg1+ takes advantage of the pin on the f2-piece.
As you noted, the invasion squares are clearly dynamic, and move with the pieces.