When Should You Sacrifice on f7?

     I saw a question on Reddit the other day where someone commented that there is a big difference between their online tactics server rating and their online game rating and they could not figure out why. The poster made the oft heard comment that they spent a lot of time on tactics and could usually find them when they knew one existed, but usually missed them in a real game. 
     For some reason a lot of players think just going over white (or black)-to-move-and-win problems over and over is tactics training. Authors, who are looking to sell their material, flood the market with books and CDs claiming that solving these exercises are the best approach to learning tactics. They don't work; if they did, players would not be making comments like the Reddit poster would they? 
     It is usually easy to solve puzzles where one is told one side is to play and it's mate in three moves because you KNOW what to look for and all you have to do is find a way to accomplish it.  I mean, they TELL you which side wins and in how many moves it can be done. Who tells you that during a game?! Just being able to find solutions does not equate to understanding. 
     IM John Watson advocates learning tactics by showing how the tactical situation came to exist. i.e. what gave rise to the tactical motif. Spielmann once commented that he could spot a combination as well as Alekhine, but he just couldn't get the positions Alekhine got. Trying to achieve that level of understanding is probably beyond the scope of most amateurs...we need a simpler approach. 
     C.J.S. Purdy gave some excellent advice on spotting tactics and I strongly recommend anything he wrote because he had an uncanny knack for explaining such things in a simple, understandable way. Another excellent book, though some of its analysis is flawed, is Vukovic's Art Of Attack In Chess. Vukovic's book is valuable because he discusses the preconditions necessary for an attack. That often involves positional considerations like control of the center, positioning of the pieces, weakening of the castled King's defenses, etc. Other factors in tactical situation include the art of calculation and the ability to make a correct evaluation of the ending position. 
     A method of spotting tactics is also helpful in limiting tactical blunders in our games. As Purdy recommended, before you make ANY move always check for tactical opportunities. There’s no point in strategic planning when there’s a winning combination in the position. The way you find tactics is not by looking at the position and trying various moves until you find something that works, or in the case of a lot of players, something that might work! See my post Tactics, the Pornography of Chess.
     At the beginning the f7 pawn is black's weakest spot and if you want to see how the attacks against f7 go, the Hanham variation of the Philidor Defense is a good place to start. For a quick discussion, see an excerpt from Join Edwards book, Teach Yourself Visually HERE and scroll down to Chapter 8. You will also want to check out my post Two Minor Pieces or Rook and Pawn...which to choose?!   The following miniature demonstrates some of the do's and don't of the sacrifice on f7 and serves as a reminder that if black allows white to play it, it's a minefield that requires the ability to calculate accurately and make an accurate assessment of the resulting positions. Not easy for a tactically challenged amateur!
     About the players: Sir Theodore H. Tylor (13 May 1900 – 23 October 1968) was a lawyer and strong international level player despite being nearly blind. In 1965, he was knighted for his service to organizations for the blind. He was Fellow and Tutor in Jurisprudence at Balliol College, Oxford for almost forty years. 
     Born in Bournville, Tylor learned to play chess at age seven. His skill increased while he attended Worcester College for the Blind from 1909 to 1918.  He studied at Oxford University beginning in 1918, and captained the Oxford University Chess Club. 
     Tylor received First-class Honors in Jurisprudence in 1922 and was made an honorary scholar of Balliol College.  The next year, he became a Bachelor of Civil Law and a lecturer at Balliol College. Called to the Bar by the Inner Temple with a certificate of honor, he was made a Fellow at Balliol College in 1928. 
     Tylor competed in twelve British Championships, finishing fourth in his first appearance in 1925.  His best result was in 1933, finishing second to Mir Sultan Khan. He tied for first at the 1929/30 Hastings Premier Reserves with George Koltanowski ahead of Salo Flohr, Josef Rejfir, Ludwig Rellstab, C.H.O'D. Alexander, Daniël Noteboom, and Milan Vidmar. 
     Tylor played in the top section, the Hastings Premier, nine times beginning in 1930/1. His best finish was 6th= in 1936/7. He was first reserve for the English team at the Hamburg 1930 Chess Olympiad. Tylor won the British Correspondence Chess Championship in 1932, 1933, and 1934. Although he finished 12th at great Nottingham 1936 tournament, he had the best score of the British participants. Tylor used a special set for the blind and a special device for counting the number of moves made. He also enjoyed bridge. He died in Oxford on 23 October 1968.  Read his interesting opinion on stalemate here.
     George Koltanowski (born Sep-17-1903, died Feb-05-2000 at the age of 96) was originally from Antwerp, Belgium. He was awarded the IM title in 1950, an honorary GM title in 1988 and became an International Arbiter in 1960. The USCF also gave him the title of "The Dean of American Chess". He was most famous as an exhibitor, writer, promoter and showman known for his exploits in simultaneous blindfold play. 
     His best tournament wins were: Antwerp 1932, Barcelona 1934 and Barcelona 1935. He was Belgian Champion in 1923, 1927, 1930 and 1936. 
     Koltanowski did not to return to Europe after the 1939 Olympiad in Argentina, which coincided with the outbreak of World War II. When the Nazis overran Belgium, several of his family members perished in the Holocaust. Koltanowski was in Guatemala at the time and was allowed to immigrate to the United States, due partly because a chess-playing consul in Cuba had been amazed by one of his exhibitions. 
     His last International appearances were playing for the US Olympiad team of 1952 and a match against Henri Grob in 1953. He was also President of the USCF from 1975 to 1978.