What is Prophylaxis (chess)?
{{Chess diagram small | tright | [[Pirc Defence]]: 1.e4 d6 |rd|__|bd|qd|__|rd|kd|__ |pd|pd|__|__|__|pd|bd|pd |nd|__|pd|pd|__|nd|pd|__ |__|__|__|__|pd|__|__|__ |__|__|__|pl|pl|__|__|__ |__|__|nl|__|__|__|pl|__ |pl|pl|pl|__|nl|pl|bl|pl |rl|__|bl|ql|rl|__|kl|__ |White's next move 9.h3 denies the square g4 to the black B & N, and prepares the developing move 10.Be3 }} '''Prophylaxis''' is a term in [[chess]], as well as being a [[Prophylaxis|general idea]]. It was introduced by the [[Grandmaster (chess)|grandmaster]] [[Aaron Nimzovich]] in his book ''My system'' in the 1920s.<ref>Nimzowitsch, Aron [1927] 1987. ''My system''. B.T Batsford Ltd. {{ISBN|9789197600538}}</ref> The term refers to actions taken by a player to [[wikt:anticipation|anticipate]] and [[wikt:thwart|thwart]] the opponent's plans, and moves of these type are often called ''prophylactic moves''.<ref>Watson, John 1998. ''Secrets of modern chess strategy: advances since Nimzowitsch''. Gambit, London. Chapter 9, p211. {{ISBN|1-901983-07-2}}</ref> == Example #1 == One simple example of a prophylactic move is when a player moves a rook's pawn forward h3 or h6 to prevent a back rank mate, and at the same time prevent an enemy bishop or knight from occupying g4 or g5. In the example, mate was not an issue, but h3 was still played by world champion [[Karpov]]. Then he could develop his QB to the best place on e3. {{Chess diagram small | tright | |__|__|__|__|__|__|__|rd |__|pd|__|__|__|__|pd|__ |__|__|bd|__|pd|pd|__|__ |__|__|pl|__|__|kd|__|pd |pd|__|__|rl|__|pl|__|__ |pl|__|__|__|__|__|pl|pl |__|pl|__|bl|__|kl|__|__ |__|__|__|__|__|__|__|__ | Black to play }} == Example #2 == Other examples are so subtle that club players would probably never think about them as possible moves. In the second example Nimzovich himself was playing black. In general, he wanted to turn his KP into a passed pawn by advancing it. However, the direct ...e5 does not work well, because the black king gets pushed back: :1.... e5 :2.fxe5 fxe5 :3.g4+ hxg4 :4.hxg4+ Ke6 :5.Rd6+