A dubious knight sac in the Vienna Gambit, Steinitz Gambit Knight Variation

In my previous blog with a header,  A dubious knight sac in the MacLeod Defense,  I presented this dubious knight sac in the King's Gambit Accepted.

This time I am presenting the same dubious knight sac in the Vienna Game:  Vienna Gambit, Steinitz Gambit Knight Variation (C25). The sample game shown below was just played today in an “online” game against a 1900 plus player.

The Steinitz Gambit Knight Variation in the Vienna Gambit has the following move sequence: 1.e4 e5 2.Nc3 Nc6 3.f4 exf4 4.Nf3.

The chess.com game explorer has the following image for this opening:

According to the game explorer, there are 306 master games in its database that were played using this opening sequence. When I inquire about the continuation 4…Bc5, it returned zero number of games played.

In the actual game, when I made the move 4…Bc5, my opponent even commented that it is wrong because of 5.d4.  In fact, one of the reasons for the  Bc5  was to entice d4 from white with the intention of playing this dubious knight sac. The computer analysis at 2500 rating level does not agree in many of the moves I made. However, I have been playing this line for a long time and in many games black found ways  to win by making sound sacrifices in the game. There are a lot of tactical opportunities in this line because white's king is exposed as it comes to to the middle of the board.  These sacrifices are apparently rejected by the 2500 rating computer analysis, marking them with question marks. However, they are actually sound. Following is the image of the game after 6...Qh4+.

I am showing below the game with the computer analysis which I believe does not capture many alternative moves like the moves I played. Some games I have on the same line are presented at the end of my previous blog,  A dubious knight sac in the MacLeod Defense.

This knight sac appears to me to be a sound move for black to make. It should however remain dubious for white because accepting the sac has been proven to be dangerous.

If you don’t think this move is sound, I will be happy to hear why and be prepared for a friendly game with me on this line. Cheers!