"In administering force, one's soldiers become like rolling logs and stones. The nature of logs and stones is to be still if secure, to move about if endangered, to stop if square, and to move if round. Thus, the force of skilled warriors is like round stones rolling from a thousand ​jen high mountain. Such is force."
- Sun Tzu

Book 5 is filled with many metaphors and similes, and this concluding passage gives us our final metaphor: logs and stones. This passage reiterates and reinforces the point made in the previous one.

For Sun Tzu, force comes from two critical factors: positioning and adaptability (which is another aspect of jie, or timing). Soldiers who are in a safe, secure position will be still and quiet. Soldiers in an unsafe, dangerous position will be agitated. Soldiers who are "square" - i.e. who are stubborn or rigid - will be hard to move or direct. But soldiers who are "round" - who "go with the flow" and adapt to whatever ground they're in - will be able to gain momentum and perform effectively.

The key, for Sun Tzu, is having a general who is able to calculate the right position (i.e. a high enough mountain) and the right moment to command his soldiers to strike (i.e. release his logs and stones).

In your own life, the same principles apply. The position from which you try to achieve your goals must give you the momentum you need to overcome obstacles, even if you make mistakes (which you inevitably will). The whole idea behind strategy is to make winning easier.

Such is the power of shih​.

"Therefore, the skilled warrior seeks [victory] through force, not through reproaching his soldiers. In this way, he is able to select soldiers and allow for force."
- Sun Tzu

For Sun Tzu, victory is achieved when the army is settled in a position of overwhelming power over the enemy. This position is what we may call a position of shih, or force. Achieving shih is not done through demanding more from one's soldiers, making them work harder and harder, but from a series of calculations in which the army has accumulated a number of key advantages over the enemy.

Thus, the general's focus is never, "How can I make my soldiers work harder to defeat the enemy?" - but rather, "What position must we occupy that will give us a huge advantage over the enemy?" Once the army is in this position, then the general need only select a few key soldiers and let the position itself do the majority of the work in defeating the enemy.

This is a key principle to remember in your own life. Success is not simply a matter of working hard. It is a matter of working hard at attaining a few key, yet hidden or unnoticed vantage points - a certain relationship with a powerful figure, a certain reputation for credibility in the marketplace, a certain position at work that gives you key information about the company.

It's from these key positions that you can take simple actions to increase your chances of success. 

"Therefore, one skilled at moving the enemy positions himself such that the enemy must follow, gives such that the enemy must take. Using advantage, entice him. Using soldiers, displace him. Using a solid force, await him."
- Sun Tzu

Here Sun Tzu touches upon the psychological aspect of warfare. Force, for Sun Tzu, doesn't mean forcing - in the sense of coercing the enemy to fight. Rather force is the effect of the accumulation of advantages in one's position such that the enemy is overwhelmed. This is the essence of shih. 

Building shih means setting the enemy up - giving him bait that he is sure to try to grab, putting him in situations that he is sure to respond in a specific way. When this occurs, the army is in control of the dynamic of the battle.

To achieve this, Sun Tzu outlines a three part strategy. First, entice the enemy with some kind of advantage. Bait him with something that he must take. Next, use select soldiers to engage and frustrate him. The objective of these soldiers is not to defeat the enemy, but to displace him - to move him from where he thought he was headed. Lastly, use the main, concentrated force to surprise him and put him off balance. Psychologically, this will cause him to divide his forces and chaos will ensue. 

In your own life, this strategy can produce great results. First, you must identify who your enemy or obstacle is. Is it a coworker? Is it another prospective employee? Is it a competitor? Is it yourself?

Next, you must figure out and employ some bait that will entice that enemy. What will make that person move in a specific direction? Is it the prospect of money? Is it the prospect of hurting you? Is it love or attention?

Next, you must aim to block your enemy from getting that bait. If it's a coworker, perhaps you send him down on a journey with a project that will take his time. If it's a competitor, perhaps you signal that you are going to move into a market that he or she will want to beat you to. If it's yourself, perhaps you develop a task or project that will focus your time and energy away from a bad habit (e.g. social media, smoking, overeating, etc.). 

Lastly, you must have a secret, concentrated action that you take or can take to secure a position of advantage over the enemy. Perhaps, in distracting your coworker with a project, you get closer to your supervisor or the executive leadership in your company.

Or in distracting your competitor with going into a market, you are creating a new product that will surprise your competitors in an existing market that you are in. Or in working on that project at home to distract you from your bad habits, you are actually developing "good" habits that get you further along in your aspirations.

This three part strategy - entice, displace, and surprise - forms the essence of Sun Tzu's battle strategy and can be used to great effect in a wide number of situations.

"[In battle,] chaos is produced from order, cowardice is produced from bravery, and weakness is produced from strength. Chaos [from] order is a matter of calculation. Cowardice [from] bravery is a matter of force. Weakness [from] strength is a matter of positioning."
- Sun Tzu

Here Sun Tzu expounds on the effects proper surprising can have on the enemy. The army's order produces chaos in the enemy. To achieve this, the army must have made detailed calculations.

The army's bravery produces cowardice in the enemy. To achieve this, the army must have sufficient momentum or force to confront the enemy and keep them off balance.

The army's strength produces weakness in the enemy. To achieve this, the army must have a well-protected position that keeps it from being defeated.

We see here what is necessary, for Sun Tzu, to be successful in battle: calculation, force, and positioning. When the army has all three, then it can create complete chaos in the enemy.

Notice how Sun Tzu doesn't say anything about the size of the army, the  quality of its weapons, or even the ferocity of its warriors. Defeating the enemy is a matter of shih and jie - force (or momentum) and timing.

In your own life, these you must have these same qualities to succeed. You must make detailed calculations. You must move with surprising force. You must always first establish a strong position that protects you against loss. Take opportunities that are within the grasp of the position you have developed for yourself, and do so with speed.

Always make sure you have force and timing on your side when you take action. This helps protect you against loss and gives you huge control over the dynamics of competition. 

"So many, so disorderly! The fighting is chaotic, yet does not permit chaos. Completely chaotic! The positioning is round, yet does not allow defeat."
- Sun Tzu

Sun Tzu here contrasts the appearance of the battle from its underlying reality. Though the battle appears chaotic and confusing, because the army has planned the surprise properly, it is able to maintain control and not be defeated.

This is the benefit of having planned proper surprises. Though everyone else may be scrambling, trying to figure out how to stop you, you are the one in control and therefore can prevent defeat.

"The swiftness of rushing water as it moves rocks - such is force. The strike of a hawk as it kills [its prey] - such is timing. Thus, for those skilled in war, their force is dangerous, their timing concise. Force is like the stretching of a crossbow; timing is like the pulling of a trigger."
- Sun Tzu

This passage is filled with imagery on two key aspects of 'proper surprising': force (or shih) and timing (jie). For Sun Tzu, in order for a surprise to work, one needs an accumulation of advantages - just as water needs momentum in order to move rocks.

At the same time, one needs precise timing in order to apply the minimum amount of force at the most vulnerable place for the enemy - just as a hawk uses precision in killing its prey in one strike.

Thus, proper surprising is not simply surprising the enemy, but surprising the enemy at strategic weak points that can completely throw the enemy off balance and create opportunities for winning - even if the army has fewer soldiers than the enemy. What matters is not the size of one's force, but one's ability to surprise the enemy precisely at the enemy's most vulnerable points.

In your own life, you must try to incorporate force and timing to achieve success using the minimum amount of effort or resources. Most people think that success is a matter of working harder, accumulating years and experience in a specific area. The true strategists of life carefully select specialized areas where they can quickly, more easily, but covertly apply a minimum of force.

For example, for that promotion at work, you may only need to befriend a few important people - actively soliciting their advice, doing favors for them, showing support for them. This may be enough to make a great impression. Likewise, with business, it may be enough to network with a few important influencers - to get their support, advice, and friendship. They can do well to promote your business to their own fans or supporters.

"There are no more than five [musical] notes, but all the variations of the five notes cannot  successfully be heard. There are no more than five colors, but all the variations of the five colors cannot successfully be seen. There are no more than five flavors, but all the variations of the five flavors cannot successfully be tasted. With battle force, there are only 'proper surprises', but all the variations of proper surprises cannot be successfully exhausted. Proper surprises give birth to each other as if in an endless circle. Who can exhaust them?"
- Sun Tzu

Through analogy, Sun Tzu  is telling us a very important point about warfare: to achieve total victory, the army must be creative. Just as a composer uses the notes on a musical scale to develop endless musical compositions and arrangements, the general can use endless variations of strategic surprises to engage and defeat the enemy.

Using strategic surprises depends on understanding the enemy's psychology - understanding what the enemy sees as normal and what goes beyond their comprehension or expectation. Because every enemy is different, what the enemy sees as normal may change. This is why the tactic of 'proper surprising' can never get used up.

In your own life, you must adapt to the psychology of the obstacles or enemies you face. You must understand what your enemy sees as normal and what is beyond their anticipation or comprehension. Understanding these two key pieces of information allows you to develop a strategy that engages and surprises them, allowing you to build momentum.

"Therefore, those skilled at creating surprises are as limitless as the Heaven and Ground, and as tireless as the Jiang River. They end and return to the beginning, just like the sun and moon. They die and return to birth, just like the four seasons."
- Sun Tzu

​Sun Tzu speaks in similes here to emphasize the effectiveness of the tactic of 'proper surprising' in warfare.

Being limitless, proper surprising changes according to the situation. Being tireless, it can always be utilized. Ending and returning, it never gets old and never stops. As Sun Tzu emphasizes later in the book, proper surprising are like the notes a musician plays on an instrument. Although the notes stay the same, the endless variation gives rise to incredible effects.

It is these qualities that you want to take away in your own life. Do not get stuck into thinking that the way to success has to be about habit, about consistency, about doing the same thing over and over to achieve a result.

Success is about creativity. What is necessary to succeed changes according to your circumstances - you have to know how to adapt and apply proper surprising to that situation.

Once you've reached a position where you are prepared to take advantage of opportunities that pass you by, you must use proper surprising - or strategic surprising - to actually make moves.

"Generally in battles, use the proper to join [the enemy], use surprise to win."
- Sun Tzu

Here Sun Tzu defines how to use what he calls "proper surprising." It is through proper surprising that one is able to receive a larger an enemy and prevent defeat. This requires the use of deception.

As we talked about in Book 4, the deception has two aspects: concealment and surprise. Proper surprising involves utilizing both aspects of deception to create momentum in battle.

First, the army must use "the proper," that is, common, straightforward, expected lines of attack, to engage the enemy. Once the enemy has been lulled into thinking he understands the situation, the army then does an unexpected, surprise attack or maneuver that throws the enemy off balance, thus tipping the dynamic of the battle in the army's favor.

Thus, it is through the proper that one conceals one's positioning, and it is through surprising that one utilizes it. It is Sun Tzu's equivalent of the jab-jab-hook.

In your own life, to gain momentum, you must follow the same principle. On the surface you must follow the rules, do what is appropriate, engage in expected ways. Conceal your plans and intentions and make the appearance of following the crowd.

Once you are in a position to attack, however, you must move with speed and take a line of least expectation. All this, of course, requires being in a strong position to attack, which is why Book 4 (on positioning) comes before Book 5.

It is when you attack with speed, using the element of surprise at critical points, that you gain momentum and control over the dynamic of your situation.
 

"In general, to manage the many as you would manage the few - use ratios. To fight the many as you would fight the few - use superior positioning. To enable the many soldiers of the army to receive the enemy and not be defeated - use proper-surprising. To apply the army's position so it is like throwing a whetstone against an egg - fill the emptiness."
- Sun Tzu

The title of Book 5 is a word that is very difficult to translate into English - shih. The term roughly translates to force, momentum, energy, power, potential. The terms I prefer to use to translate are "force" and "momentum," as these reflect Sun Tzu's usage throughout The Art of War.

This passage reflects the previous two books, the current book, and the next book. By referring to the ratios, Sun Tzu is referring to the size ratios in Book 3, "Planning Attacks." By referring to positioning, he is referring to his approach to positioning in Book 4. By referring to "proper surprising," he is referring to the strategy he will explain in Book 5. And lastly, by referring to "fill the emptiness," he is referring to the next book, on "Emptiness and Fullness."

A key point to understand in this passage is Sun Tzu's economical perspective towards strategy. Sun Tzu's concern is always with the numbers, or size, of the army. The ideal is to have an army that is bigger than the enemy's; this offers much more flexibility.

However, Sun Tzu's point is that the principles of warfare are the same: whether the enemy is bigger or smaller, one must still adapt to and surprise the enemy. Total victory requires being economical, and being economical requires understanding and adapting to the enemy, including his size and his psychology.

In your own life, the principles are also the same: you must understand and adapt to the enemies or obstacles you face in life, no matter if they seem more or less intimidating than you can handle. You must understand the size and impact of the obstacles as well as how they work or think.

If your goal is to tackle a promotion or job, you must understand how the hiring managers think and the size of the company. If your goal is to build a business, your goal is to understand your competitors - their size and psychology.

Adaptation and surprise make up the essence of Sun Tzu's philosophy.