So, this trap is really popular, a 4 move checkmate, it is possible for both black and white, the target squares should always be f7 for white and f2 for black. Why? Because before castling, the only protecters of those squares are the kings. Once we look at white's trap, we will know how black can achieve that.
OK, so a classic C00 King's Pawn game, 1.e4 e5 2.Qh5, if e6, Qxe5+, anything blocks, Qxh8 +/-, so black defends e5 with Nc6, then Bc4. Notice how the B and Q are eyeing down f7, black should have played Nh6, defending f7, but inexperienced players will most likely develop a piece while attacking the queen, Nf6, a ??????????, not only ??. Now play Qxf7#. If the knight was on h6, then the queen would be killed instantly.
A common mistake is Bc4 first, a chance to play Nf6 first by black, stopping all threats. Although this may not work every time, you should try it in your next game, and if luck is on your side, you will receive the “Quick Knockout” award.
Lesson by Saptanshu Deb