Chess Board
[ECO code C21]
TRANSPOSITION
CENTRE GAME to PHILIDOR'S DEFENCE
White developed his KKt for a Q-supported attack against Black's newly doubled QP on Q5(d4).
Black rarely transposes into an "Exchange Varation" of the Philidor Defence by pushing his Queen's Pawn out to free his QB, offering a 4.QxP or 4.KtxP exchange. B-Alt.
    White  Black    Transp.White Black
 1. P-K4   P-K4		   (1.)	
 2. P-Q4   PxP		   (3.)
 3. Kt-KB3 P-Q3		   (2.)
Continue: Transpose or Undo or Jump or Clear