Are You Strong Enough to Play the Ponziani
Bontrager the move Qd2 does not work because of this follow up
Qd2 Bxg5
Qxg5 Qxg5
Nxg5 Rxb3
also after Qd2 the rook sacrifice with Rxf3 probably works for Black.
Yes! 17. Nf6! This move was found by pattern recognition. This type of sac has happened before. The idea to see that the move is at least a possible move and then start your analysis if it is good or not?
This was a vote chess game Ponziani Power vs Black Knight Chess. Our group analyzed this move and almost abandoned it but then found a resource against one of the defenses. Notice our sac is on f6 and I will continue the game...
24. Rxf6 gxf6 25. Re7 Qg8 26. Qxf6 and white will mate.
24. Rxf6 gxf6 25. Re7 Qxe7 26. Qxe7 and white has winning advantage.
24. Rxf6 Qxf6 25. Re8+ Rxe8 (25... Kh7 26. Bc2+) 26. Qxe8+ Kh7 27. Bg8+ Kh8 28. Bf7+ Kh7 29. Qg8#
24. Rxf6 gxf6 25. Re7 Qg8 26. Qxf6 and white will mate.
24. Rxf6 gxf6 25. Re7 Qxe7 26. Qxe7 and white has winning advantage.
24. Rxf6 Qxf6 25. Re8+ Rxe8 (25... Kh7 26. Bc2+) 26. Qxe8+ Kh7 27. Bg8+ Kh8 28. Bf7+ Kh7 29. Qg8#
Yes, you are correct. This is a 2nd sacrifice on the square f6! This one a lot easier to see than the first one. [unusual to have two sacrifices on the same square in one game.]
The game actually ended with 29. Qg8+ which is your 3rd line.
Here I will give the entire game with your ending [which was actually played]
The game was a Ponziani which had two sacrifices [for White] on the f6 square. I have now given the full game with the two sacrifices plus a rather unique ending/checkmate.
However, since you were interested will give you the end of another game It is find the best move difficulty hard