Black took the opportunity to advance his KP to the vacant centre
for control of Q5(d4), and freed his KB for a potential
..B-QKt5 pin after any White Kt-QB3. White develops his Queen's Knight to the
vacated Q2(d2), deterring 2..B-QKt5
and 2..P-K5. Often becomes a
King's Indian Attack.
W-Alt.