“Ground on which each side has liberty of movement is open ground.”
When both can move freely, no one holds the lock; use mobility, not fixed holds.
Chapter 11’s fourth ground: ground on which each side has liberty of movement is open ground, and its rule — coming a few verses later — is to keep your forces together, trusting mobility over fortification. The definition is the lesson: when nobody can be locked in, nobody can lock anything either. Position is rented here, never owned.
An unregulated services niche where any firm can hire any talent and serve any client — genuinely open ground. One agency spends its capital building a fortress: an office, a brand, long-term exclusives that bind nobody. A rival stays light: senior bench, fast assembly, moving to where demand spikes this quarter. When the demand pattern shifts, the fortress is a liability and the mobile firm is already there. On open ground, speed of relocation is the only moat.
Open ground is not license for aimless wandering — mobility is used toward objectives like any other asset, just not converted into fixed holdings. And few markets are purely open; most are open in some layers (talent, channels) and narrow in others (data, regulation). The discipline is knowing which layer you stand in before choosing walls or wheels.