White wishes that his f-pawn wasn't blocking the a1=h8
diagonal, otherwise he could mate Black in the corner with the
combined action of the bishop & rook:
So White hatches a plan to achieve his 'fantasy'
position. The plan starts with a clearance sacrifice:
1.Qxg6+ fxg6
White's first objective has been achieved: clearing a
path for the advance of the f-pawn.
2.f7+ Qxf7
White's last move was a rare double - a second
consecutive clearance sacrifice. The pawn advance cleared the
a1-h8 diagonal for the bishop, and gave check in the process, forcing
Black's reply and preventing him from trying to escape the trap.
3.Rh8 mate
Remember our 'fantasy' position, the one we envisioned
back at the beginning of this problem? Compare it to the
position above.
So here is another lesson outside the tactics
demonstrated here: visualize the ideal position you would like to
achieve, then work out a plan to reach that position!
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