After the four initial moves by both players in a chess game, the following position was obtained:
(BLACK)
+---+---+---+---+---+---+---+---+
| R | N | B | Q | K | B | | R |
+---+---+---+---+---+---+---+---+
| P | P | P | | P | P | P | P |
+---+---+---+---+---+---+---+---+
| | | | | | | | |
+---+---+---+---+---+---+---+---+
| | | | P | | | | |
+---+---+---+---+---+---+---+---+
| | | | | | | | |
+---+---+---+---+---+---+---+---+
| | | | | | | | |
+---+---+---+---+---+---+---+---+
| P | P | P | P | P | P | P | P |
+---+---+---+---+---+---+---+---+
| R | N | B | Q | K | B | | R |
+---+---+---+---+---+---+---+---+
(WHITE)
Reconstruct the game so far.
1. N-f3 N-f6
2. N-e5 d5
3. N-c6 N-d7
4. Nxb8 Nxb8
Clever problem! Where'd you get it, pc?