Chess Board
[ECO code C42]
PETROFF'S DEFENCE
Jaenisch Variation
White moves his king's side Rook to K1(e1), planning an attack on the open king's file.
Black develops his Queen's Bishop to the king's file, for equality with a sound defensive formation.
    White  Black     6. B-Q3   B-K2
 1. P-K4   P-K4	     7.	0-0    Kt-QB3
 2. Kt-KB3 Kt-KB3    8.	P-B4   Kt-B3
 3. KtxP   P-Q3	     9.	Kt-B3  0-0
 4. Kt-KB3 KtxP	    10.	PxP    KtxP
 5. P-Q4   P-Q4	    11.	R-K1   B-K3
Example ends: Undo or Jump or Clear