One of the chief points of the Evans Gambit is that Black's Q Kt is driven
to Q R 4, and has to remain there for some time inactive, so that Black is,
for the time being, practically a piece _minus_ for the defence. White
must, therefore prevent as long as possible this Knight from coming into
play. It will be seen that Black could not have played 10. ... Kt takes B,
because in such case 11. B takes K Kt P, winning the exchange.