11. The Nine Situations
On open ground, do not try to block the enemy's way.
Because the attempt would be futile, and would expose the blocking force itself to serious risks. There are two interpretations available here. I follow that of Chang Yu. The other is indicated in Ts`ao Kung's brief note: "Draw closer together"—i.e., see that a portion of your own army is not cut off.
On the ground of intersecting highways, join hands with your allies.
Or perhaps, "form alliances with neighboring states."