Chess Board
[ECO code C23]
BISHOP'S OPG. TRANSPOSITION
PHILIDOR VAR. towards PETROFF GAMBIT
Black pushed his QPawn out to support his KP in anticipation of 4.P-Q4, and freed his QB.
White transposes towards the line of the Petroff Gambit by developing his King's Knight to KB3(f3) to support a 5.P-Q4 advance.
    White  Black    Transp.White Black
 1. P-K4   P-K4		  (1.)
 2. B-B4   B-B4		  (2.)
 3. P-QB3  P-Q3	    (3.	Kt-KB3 P-Q3)
 4. Kt-B3	    (4.	P-B3	   )
Continue: Transpose or Undo or Jump or Clear