As the old chess legend goes, in one of his games GM Alexander Ivanov played Nf3-g5 and after his opponent answered with h7-h6, Alexander realized that the only reasonable move he had was Ng5-f3. After pondering for a while, GM Ivanov said "Russians do not retreat!" and played Ng5xf7, which was a completely unsound sacrifice. Unfortunately the legend doesn't reveal the outcome of the game. I am not sure how this legend started, but I am absolutely positive that it never really happened (or at least not in a tournament game). I know GM Ivanov very well, played him many times and can assure you that he is a perfect example of good sportsmanship and therefore would never talk during a tournament game. Nevertheless, whenever I see the Nxf7 sacrifice I cannot help but remember this legend. I even call this sacrifice the "Russians do not retreat" sac! You all probably saw many examples of such a sacrifice. I bet almost every single chess player fell a victim of this sacrifice in the "Fried Liver Attack":
We analyzed this variation here: http://www.chess.com/article/view/myth-and-reality
The Nxf7 sacrifice in the Fried Liver Attack leads to an unclear position, but in the next famous game of Mikhail Tal, Black immediately found himself in big trouble.
In the following game the best student of Mikhail Tal made his teacher very proud. There is a scary (or funny, depending on your perception) story about this game. I played the same World Junior Championship and remember that very frequently the group of Soviet players (future GMs Shirov, Dreev, Ulibin and myself) walked around the city before our games. But Alexey Shirov always liked to go his own way, which is something that really helped him in his chess career but could have cost him dearly that particular day. He went far away from the hotel and in some remote area (and I assume it was a bad neighbourhood) a guy pointed a rifle at him. As it turned out the guy thought that a very tall future super GM was going to steal something from him and therefore he didn't mean any harm but used the rifle for self defense. Anyway, the same evening Alexey produced the following gem. I guess it was easy for him to play because after a near death experience, who cares about a little horsie?
Unlike the original "Russians do not retreat" sacrifice, the Knight can be sacrificed on the 'f7' square even if it is not attacked by a pawn and it can start on a square other than 'g5'.
Finally let me show you a relatively recent game played by two elite GMs. It was revealed that the Nxf7 sac was the fruit of home preparation, but it has all the features of the classical "Russians do not retreat!" sacrifice: it didn't lead to a forced checkmate and yet the Black King was in constant danger throughout the whole game.
According to the reports this novelty was found by Topalov's second GM Ivan Cheparinov. I don't know how many hours the Bulgarian team and their computers spent on this opening bomb, so I won't even try to determine where Black made the decisive mistake and what was a better way to defend. Just enjoy an extraordinary chess show:
I hope you'll add the Nxf7 sacrifice to your chess arsenal because you don't need to be Russian to play it!