Originally posted by Mephisto2
4.QxNg4 will win a piece for white.
well done! it is always better to explain how you got there
here is the solution of that puzzle :-)
The moves were 1.c4 d5 2. cxd5 Nf6 3. e4 Nxe4?? 1-0, on account of 4. Qa4+ winning the knight on e4
If W was able to check B on move two, then she must have opened by advancing her c or e-pawn to free white’s queen or light squared bishop sufficiently to deliver the check. However if W had moved the e-pawn, then B could have allowed checks on b5 or h5 by moving his d- or f-pawns respectively. We were told that B move the only pawn which would allow a check. Therefore W must have advanced her c-pawn instead , and b must hae move his d-pawn in respons ( to allow Qa4+) Did those pawn advance one or two squares? Well since W continued with a capture, the first move could only have been 1.c4 d5 to allow 2.cxd5. We know that on move three, W defends her attacked pawn (on d5) with a pawn move, which can only be 3.e4. At that stage, we also know that B captures white’s e-pawn. So B’s knight on move two must have been 2. …. Nf6 followed by 3. … Nxe4.
that puzzle could be solved by logical deduction but what about the quality of the actual moves?. When I composed this puzzle, I was reminded of two other opening traps
a) 1. e4 c5 2. nf3 d6 3. c3 Nf6 4. Bc2 Nxe4?? 5. Qa4+
b) 1.d4 Nf6 2. Bg5 c6 3. e3?? Qa5+
It would do us no arm to store them well in the memory, because incredibly, there have been numerous instances of players including masters falling into both traps. A little extra care and alertness can stop the list of victim from growing further!
Incidently after 1.c4 the defence 1. … Nf6 2. Nc3 d5 is playable but as the puzzle demonstrated, 1. … d5 is not to be recommended.
Stay tuned for the next puzzle!