“You may advance and be absolutely irresistible, if you make for the enemy's weak points; you may retire and be safe, if your movements are more rapid than those of the enemy.”
Irresistibility comes from striking weakness; safety comes from out-pacing pursuit; both are positional, not heroic.
Chapter 6 pairs its two guarantees: advance irresistibly by making for the enemy’s weak points; retire safely by moving more rapidly than the enemy. Attack and retreat, issued together — because Sun Tzu’s army is never committed to winning where it stands. Mobility is the license to always fight at the point of weakness and never at the point of pride.
A product team loses a head-to-head feature comparison and requests a quarter to close the gap — the instinct to fight on the strong point. The release they actually ship ignores that feature entirely and changes the metric the comparison measured. Reviewers must now rebuild their scorecards from scratch, and the rival’s advantage sits in a category nobody reads anymore.
Rapidity as safety is not speed as virtue — fleeing faster than pursuit is a specific, situational property, not a culture of hustle. A company that is merely fast, but always arriving at defended points, has speed without mobility. The pairing is the point: choose weak ground, and keep the legs to leave strong ground.