The FIDE Laws of Chess

Appendix C:   Blitz 

C1.  A 'Blitz game' is one where all the moves must be made in a fixed time less than 15 minutes for each player. 

C2.  Play shall be governed by the Rapidplay Laws as in Appendix B except where they are overridden by the following Laws of Blitz. 

C3.  An illegal move is completed once the opponent's clock has been started. However, the opponent is entitled to claim a win before making his own move. If the opponent cannot checkmate the player's King by any possible series of  legal moves with the most unskilled counterplay, then he is entitled to claim a draw before making his own move. Once the opponent has made his own move, an illegal move cannot be corrected 

C4.  Article 10.2 does not apply. .