Art of War Chapter 6: Weak and Strong Points — 虚实 Explained
Avoid strength, strike weakness — the art of emptiness and fullness
Published July 18, 2026
Key Takeaways
- Avoid the enemy's strength and strike where they are weak
- Force the enemy to prepare everywhere, making them weak everywhere
- Be like water — adapt constantly to circumstances rather than following fixed plans
Emptiness and Fullness
Chapter 6 develops the paired concepts of xu (虚 — emptiness, weakness, vacancy) and shi (实 — fullness, strength, solidity). The strategic goal is to make your own position solid (full) while forcing the enemy into weakness (empty). 'The enemy must not know where I intend to give battle. For if he does not know, he must prepare in many places.'
Sun Tzu's method for creating this asymmetry is mobility and deception. If the enemy must defend everywhere, his forces are spread thin everywhere. 'If he prepares to the front, his rear will be weak. If he prepares to the rear, his front will be weak.' The goal is to force the enemy into a position where every choice is a compromise.
The commander who understands emptiness and fullness does not fight the enemy's strength. Instead, he makes the enemy's strength irrelevant by attacking where the enemy is not. This is not about avoiding conflict but about choosing the ground on which conflict occurs.
Water as a Model
Sun Tzu uses water as the model for strategic flexibility. 'Water shapes its flow according to the ground. The army shapes its victory according to the enemy.' Just as water flows from high to low, seeking the path of least resistance, the army should flow from strength to weakness, seeking the path of maximum advantage.
The water metaphor is profound because it captures both the relentlessness and the adaptability of good strategy. Water does not fight the mountain — it flows around it. It does not force its way through obstacles — it finds the path through. Yet water is also unstoppable over time, wearing down the hardest stone through persistent pressure.
This adaptability requires the commander to abandon fixed plans. 'There is no single set of circumstances that is always favorable.' What worked in one situation may fail in another. The skillful commander adapts constantly, reading the situation and responding appropriately, like water responding to the terrain.
Modern Application
The principle of avoiding strength and striking weakness is the foundation of all competitive strategy. Identify where your competitor is over-extended, complacent, or vulnerable, and attack there. Do not challenge their strengths directly — that is their territory. Instead, make your competitor's strengths irrelevant by changing the terms of competition.
In personal development, this means leveraging your natural strengths rather than obsessively fixing weaknesses. Play to your advantages. Structure your life and work so that your weaknesses become irrelevant and your strengths become decisive. This is the strategic application of shi — positioning yourself where your natural abilities are amplified.
Frequently Asked Questions
What is the meaning of xu (虚) and shi (实) in Sun Tzu?
Xu (虚) means emptiness, weakness, or vulnerability. Shi (实) means fullness, strength, or solidity. The strategic goal is to make your own position strong (full) while forcing the enemy into weakness (empty) by attacking where they are not prepared and forcing them to defend everywhere.
What is the water metaphor in Art of War Chapter 6?
Sun Tzu uses water to illustrate strategic flexibility: water flows from high to low, seeking the path of least resistance and adapting to the terrain. Similarly, an army should flow from the enemy's strength to their weakness, adapting constantly to circumstances rather than following fixed plans.
How do I apply 'avoid strength, strike weakness' in competition?
Identify where your competitor is over-extended or complacent, and attack there. Do not challenge their strengths directly — that is fighting on their terms. Instead, change the arena of competition to one where your advantages matter and their strengths become irrelevant. Find the gaps and flow into them.