The game so far: 1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. O-O Nf6 5. d3 Bxf2+ 6. Kxf2 d6 7. Ke1 O-O 8. Nc3 Nxe4 9. Nxe4 Qd7 10. Qe2 Rd8 11. Bb5 d5 12. Bxc6 Qe6 13. Bb5 f5 14. Nc5 Rd6 15. Nxe6 Ra6 16. Nxc7 Rxa2 17. Rxa2 g5 18. Nxa8 Kf7 19. Nxg5+ Kg8 20. Qxe5 Be6 21. Qxe6+ Kf8 Current position: ``` a b c d e f g h 8 N . . . . . k . 8 7 p p . . . . . p 7 6 . . . . Q . . . 6 5 . B . p . p N . 5 4 . . . . . . . . 4 3 . . . P . . . . 3 2 R P P . . . P P 2 1 . . B . K R . . 1 ``` **Material**: White 36, Black 5 (White up +31 — black is down to just king and pawns!). Black moved the king to **f8** (escaping the check along the e6-f7-g8 diagonal). Now the king is on f8, and the white queen is on e6. **Qf7#** — The queen moves from e6 to f7 along the diagonal (e6→f7). This delivers check along the f-file (f7→f8). **Is this checkmate? Let me verify every escape route and defense:** 1. **King capture (Kxf7)**: The knight on g5 DEFENDS f7 (g5→f7 is a knight move: 1 file left, 2 ranks up). The king cannot capture the queen because it would move into check from the knight. ✗ 2. **King escape squares** (all attacked): - **e7**: Attacked by the queen (7th rank: f7→e7). ✗ - **e8**: Attacked by BOTH the queen (diagonal: f7→e8) AND the bishop on b5 (diagonal: b5→c6→d7→e8, all squares empty). ✗ - **g7**: Attacked by the queen (7th rank: f7→g7). ✗ - **g8**: Attacked by the queen (diagonal: f7→g8). ✗ 3. **Blocking**: The check is along the f-file (f7 adjacent to f8) — no squares to interpose. ✗ 4. **Piece capture of queen**: No black piece (only king, pawns, and no bishop/knight/rook/queen) can reach f7. The pawns on a7, b7, d5, f5, h7 attack squares far from f7. ✗ **CHECKMATE!** This is a beautiful finish — the queen delivers mate with the support of the knight on g5 (defending f7) and the bishop on b5 (covering e8). A perfect coordination of all three major pieces to deliver mate against a bare king.
About this game
Poolside: Laguna S 2.1 (free) had White and Poolside: Laguna XS 2.1 (free) had Black, in round 42 of Free Models. The opening was the Italian Game: Giuoco Piano (C50), reached on move 3. Poolside: Laguna S 2.1 (free) won by checkmate on move 22, with Qf7#. White finished 31 points of material up, 36 to 5. Poolside: Laguna XS 2.1 (free) made 5 illegal move attempts; its opponent made none.
In their own words
The first illegal move
Poolside: Laguna XS 2.1 (free) tried Bb4 on move 8, which was illegal: no legal move in this position matches 'Bb4'. It played Nxe4 instead.
… wait no) Actually, I'm getting confused. Let me just look at the legal moves and pick a good one. The board shows: - It's Black's turn - Black's king is on f8 - Black's rook is on g8 - Black's pieces: bishops on c5 and f8, knights on c6 and f6, queen on d8, rooks on a8 and h8 Wait, I see now - after my O-O, the board shows Black's king on g8 (from the diagram), but the FEN shows the king on f8. Let me trust the FEN. Looking at legal moves, I think **Nxe4** is a good tactical shot. Let me play it.
its reasoning, the end of it — the whole turn is in the replay above The biggest capture
Poolside: Laguna S 2.1 (free) took a queen with Nxe6 on move 15.
… - The net material gain is +6, increasing my advantage from +7 to +13. - This is winning — black will have no queen and no knights, while white still has a queen, 2 bishops, 1 knight, and 2 rooks. This is a brilliant tactical shot. Let me play it. Let me also note: the legal moves show both Nxb7 (capturing the b7 pawn) and Nxe6 (capturing the queen). I've analyzed Nxb7 and determined it's a blunder (the c8 bishop recaptures). Nxe6 is clearly the superior move — winning the queen. I should play Nxe6. This is a game-winning capture.
its reasoning, the end of it — the whole turn is in the replay above The end
Poolside: Laguna S 2.1 (free) played the last move of the game, Qf7# on move 22.
… From h7, captures on g6.). None can reach f7. The bishop is gone. No knights, no rooks, no queen. No piece can capture the queen on f7. ✓ Can the king move to any escape square? As I analyzed, all escape squares (e7, e8, g7, g8) are covered by the queen or the bishop. And the king can't stay on f8 (it's in check). ✓ Can the check be blocked? The check is along the f-file (f7-f8), with the queen on f7 and the king on f8 (adjacent). No square between them to block. ✓ **CHECKMATE!** ✓ I'll play **Qf7#**. Let me also check the UCI: e6f7. The queen moves from e6 to f7. ✓
its reasoning, the end of it — the whole turn is in the replay above