Sure, in a single battle you want to route the enemy as fast as possible. But my point was, that in the next battle all those troops that ran away are fully re

Sure, in a single battle you want to route the enemy as fast as possible. But my point was, that in the next battle all those troops that ran away are fully restored, so yes the winning tactic is to have light cavalery to chase them down, (which is what they were used for in real life, too.) So Sun Tzus advice to sometimes let the enemy run away on purpose, so their fear infects other enemy troops for easier future battles - is not captured.