“The good fighters of old first put themselves beyond the possibility of defeat, and then waited for an opportunity of defeating the enemy.”

Secure your own position before reaching for the win; survival creates the chance to strike.
Chapter 4 opens with its governing idea, and it is an ordering principle rather than a tactic: the good fighters of old first put themselves beyond the possibility of defeat, and then waited. Everything in the chapter is a consequence of this sequence. Where Chapter 3 asked how to break the enemy, Chapter 4 asks what makes you unbreakable — because only an undefeatable position can afford to wait for the offensive half of the book’s program.
A boutique agency lives or dies by one client — 60% of revenue. Its founder is brilliant at pitching new work and terrible at the unglamorous move: diversifying. The year the anchor client is acquired and the retainer dies, brilliance turns out not to be a strategy. The rival agency of equal talent had capped any client at 20% two years earlier — beyond the possibility of that particular defeat — and simply waited out the same market.
Being undefeatable is not being invincible everywhere — no such position exists, and Sun Tzu spends whole chapters on ground where even good armies lose. It is removing the specific defeats you cannot survive: the single point of failure, the unacceptable concentration, the fatal dependency. The standard is categorical only about the risks that would end you.