The Art of War emphasizes achieving victory over fewer forces to ensure sustained combat effectiveness.

To succeed, you must leverage time and space.

How do you beat twice your numbers with only half the force?

While the enemy’s 20,000 haven’t yet consolidated, you hit with your 10,000, devouring 5,000 of theirs. Then you quickly shift to another battlefield and eat another 5,000. In the chaos, you strike again and take another 5,000. Now the remaining 5,000 are confused, unsure of how many opponents they’re facing, and their ranks collapse from within.
This is how you leverage time and space.
Your total force may be 20,000, but at any specific moment and location, the advantage is yours: you’re concentrating your 10,000 against their 5,000.