“Ground the possession of which imports great advantage to either side is contentious ground.”
Where possession matters hugely to both, the struggle is justified; hold it or deny it.
Chapter 11’s third ground is defined by value, not shape: ground the possession of which imports great advantage to either side is contentious ground. No rule against fighting here — the fight is the point. What the definition supplies is triage: most ground is not worth contesting, and the commander who cannot name his contentious ground is condemned to contest everything.
In a software category, the contentious ground is the developer standard: whoever owns the default integration owns the flow of new apps. Two vendors pour resources into conferences and features — ground that advantages neither durably — while a third quietly commits everything to the standard’s committee and reference implementations. When the standard consolidated, the fight everyone had been watching turned out not to have been the fight.
Contested by the enemy is not the definition — valuable to both is. Much of what companies contest is merely rival-touched, fought over because the competitor is there, not because possession decides anything. The verse’s discipline is ruthless value-naming: what ground, if held, changes the outcome of the whole war? That one is worth the fight it will cost.