I've heard the Art of War is overrated trash, actually (not my words, just reporting that it has a substantial hatebase). What exactly is it like?
In less inhibited moments, I sometimes say that Sunzi was a trash can.
Many of the things that one can learn from modern strategy texts are also in the thirteen-chapter text attributed to Sunzi,
Master Sun's Military Methods. Many of them are tried and true tenets of military philosophy not obvious to every observer, like the overwhelming importance of a relentless pursuit. Other things are common sense (although most observers would generally say that strategy is a fundamentally common sense topic): flexibility is a good thing, actionable intelligence is a good thing, morale is important, don't fight battles you don't have to, don't let yourself get boxed in, make sure you have supplies, etc. Others are essentially matters of definition; the author of the thirteen chapters, for example, spends a great deal of time proving that force multipliers exist. With all that said, I don't think that many people would say that the thirteen chapters completely lack value and that the reader will learn nothing about warfare if she reads it.
Many of the things that one finds in the text are specific to the classical Chinese idiom and are not that useful for the modern student of warfare. Other times, the author contradicts himself, making a universal statement of truth in one sentence and specifically denying it in a later chapter. Now, this is not necessarily wrong. Warfare is in most particulars a situation in which the commander balances a large number of competing risks. It is not wrong to point out that certain kinds of ground are disadvantageous to fight on, and then to also point out that accepting the risk of fighting on bad ground in order to take advantage of some enemy vulnerability is often a good idea. The author of the thirteen chapters' language is overly prescriptive in many places, but that's an artifact of the genre and possibly also of the translation. Sometimes, the author combines good advice with bad, especially in his description of the demeanor of a commander.
The author is also straight-up wrong about some things that are not merely a matter of historical context. Most egregiously, the author fosters a belief in what is possible in war that is not realistic: that a commander can orchestrate victory beforehand, and that battle is merely a bit of dramatic irony, playing out what has already been decided. Like virtually every author in the world before the publication of
Vom Kriege, the author of the thirteen chapters badly understates the extent of fog, friction, and chance in warfare. Instead, the author's understanding of warfare is highly schematic: there are nine contingencies, five traits dangerous in a commander, five phases of battle, and so on. Many of the author's ideas about warfare seem to rely on an obliging enemy, one who can be easily understood and duped into doing exactly what you want him to do. This may be a useful thing for a literary general interested in royal patronage to project - the image of an infallible master with all the tricks who can make opponents look like fools - but it is an actively counterproductive way to view warfare.
Some readers who
are well versed in the study of warfare have insisted that they can read all sorts of higher-order concepts in the
Military Methods. For example, there has been at least one person to argue to me to my face about the meaning of the following passage:
Sunzi bingfa 4.14-15 tr. Ames said:
Therefore, the expert in battle takes his stand on ground that is unassailable, and does not miss his chance to defeat the enemy. For this reason, the victorious army only enters battle after having first won the victory, while the defeated army only seeks victory after having first entered the fray.
This person steadfastly believes that the quoted text is in fact an example of operational art, a concept that did not even exist until the twentieth century. Reading this into the text here is deeply anachronistic and also betrays a misunderstanding of the concept of "operational art", which is a bit more complicated than trying to make sure one is adequately prepared for battle. Note again here that Sunzi's words imply that it is even possible to ensure that victory in battle is "unerring" (4.13), when in reality most soldiers now fully understand that battle is the most chaotic and most risky aspect of human endeavor. Battle is, fundamentally, a lottery, and too many things can go wrong for even the greatest commander of all time to guarantee victory. Adequate preparation and planning are undeniably valuable things, but the means that the author of the
Military Methods attempts to use to get them across are suboptimal. Here, overly prescriptive language leads not to a minor contradiction but something that is actively dangerous.
You might think that readers are generally smart enough to know what is good about the
Military Methods and what is bad. You would be wrong. Even soldiers succumb to the notion that there is such a thing as a way to guarantee victory.
With all that said, there is nothing wrong with a good strong active read of
Master Sun's Military Methods. The text is extraordinarily short; the thirteen chapters ought to take you about twenty minutes to read and annotate.
The thing I don't like about the text is not the text itself. The text was a product of its time and has limitations like any other attempt to discuss warfare in any depth. The thing I don't like about the text is actually people's propensity to act as though it holds all the keys to warfare, that people who read it are automatically geniuses and people who do not read it, or who ignore its precepts, are imbeciles. The level of unthinking hero-worship one finds with the
Military Methods is kind of astounding. It's much worse than the Clausewitz-worshipping
Wehraboos, who for all their slavish obedience to the old master at least avoid being egregiously, disastrously wrong about any aspect of warfare. Avoid the hero worship, and you'll be all right.
EDIT: clarified one point