A Rook for the Back Rank

The game, move by move

A Sicilian, four knights

1. 1. e4 King’s pawn
2. 1… c5 The Sicilian
3. 2. Nc3 Developing
4. 2… Nc6 And Black
5. 3. Nf3 The second knight
6. 3… e6 e6, solid
7. 4. d4 The centre
8. 4… cxd4 Taken
9. 5. Nxd4 Recaptured
10. 5… Nf6 The fourth knight out
11. 6. Ndb5 Ndb5, eyeing c7 The knight heads for the fork. It gets there, it takes the rook, and it is never heard from again.
12. 6… Bb4 The bishop pins c3

The fork on c7

1. 7. Bf4 The bishop to f4, holding c7
2. 7… Nxe4 The pawn, taken Black takes on e4 and allows the fork. It is not an oversight: the knight has to spend two moves collecting the rook, and two moves is what this position costs.
3. 8. Nc7+ The fork, with check
4. 8… Kf8 The king steps aside Kf8 gives up castling and the rook in the corner, and connects nothing. Every black piece is already where it needs to be.
5. 9. Nxa8 The rook, taken A whole exchange, on move nine, and the knight is now on a8 behind Black’s pawn on a7. It has no moves that do not lose it and it makes none.
6. 9… Qf6 The queen comes out

Everything at e1

1. 10. Qf3 The queen to f3, defending
2. 10… Nxc3 The knight takes on c3 Winning the piece back and putting a knight next to White’s king with a bishop behind it.
3. 11. Bd2 The bishop to d2
4. 11… Nd4 The second knight to d4 It covers e2 from here, and e2 is one of the five squares that matter at the end.
5. 12. Qd3 The queen to d3
6. 12… Qe5+ Check, from e5
7. 13. Be3 Blocked with the bishop
8. 13… Na4+ Check, from a4
9. 14. c3 Blocked with the c-pawn The pawn steps to c3 to stop the check, and it is the pawn the bishop takes to give mate.
10. 14… Nxb2 The knight takes b2 A pawn, and the square d1 with it. White’s king has not moved and his rooks have never been connected.
11. 15. Qb1 The queen to b1 The last move, and there was nothing better: everything Black owns is already aimed at e1.
12. 15… Bxc3# Checkmate, on c3 The bishop takes the pawn and gives check down the diagonal. The knight on b2 covers d1, the knight on d4 covers e2, the bishop covers d2 — and f1 and f2 are White’s own bishop and pawn. The knight that took the rook is still on a8.