Course Hero. "The Art of War Study Guide." Course Hero. 14 Dec. 2017. Web. 18 July 2018. <https://www.coursehero.com/lit/The-Art-of-War/>.
Course Hero. (2017, December 14). The Art of War Study Guide. In Course Hero. Retrieved July 18, 2018, from https://www.coursehero.com/lit/The-Art-of-War/
(Course Hero, 2017)
Course Hero. "The Art of War Study Guide." December 14, 2017. Accessed July 18, 2018. https://www.coursehero.com/lit/The-Art-of-War/.
Course Hero, "The Art of War Study Guide," December 14, 2017, accessed July 18, 2018, https://www.coursehero.com/lit/The-Art-of-War/.
This final chapter of The Art of War requires more than the usual commentary to understand Sun Tzu's meanings. Sun Tzu begins with a discussion of the costs of waging war, claiming that "an army of one hundred thousand ... will amount to a thousand pieces of gold daily." He then turns his attention to the importance of foreknowledge to a prince and a general. Valuable foreknowledge of a potential enemy that may seem to the ordinary person to have come from supernatural sources can, according to Sun Tzu, be obtained by employing five different kinds of secret agents. These agents can work together as the "Divine Skein," giving a sovereign an advantage over his enemy.
"Native" agents are those from the enemy's country, while "inside" agents are those already inside the opposing army's structure. With these two kinds of agents, it is important, as Tu Mu points out, to seek out anyone who has been slighted, underpaid, or mistreated, or is simply greedy or ambitious. Anyone nursing a grudge may be susceptible to flattery, generous bribery, or persuasion by an emotional or logical appeal. Such agents can pass on significant information, while simultaneously working to "create cleavages between the sovereign and his ministers."
"Doubled" agents are spies the enemy has sent who can be bribed, then used to covey false information back to the enemy. However, as commentator Li Ch'uan points out, these kinds of agents must be handled with great care and caution. A thorough knowledge of the kind of person a doubled agent is will indicate the type of enticement to which he will most likely be susceptible. On the other end of the spectrum, "expendable" agents are those entrusted to feed the enemy leaked information that is deliberately false. Such agents are expendable because if caught in the deception, they will be killed. "Living" agents, on the other hand, are those who return with intelligence for the general's ears only. This information can be used to gain an advantage over the enemy. This is what Tu Mu calls "'mouth to ear' matters." This in itself is perilous, because if a living spy has been compromised, premature notice of secret plans might be leaked out, in which case such an agent—and anyone else to whom he may have spoken—should be killed immediately. Tu Mu follows up on this by describing the kinds of details a good and well-rewarded spy can provide the attentive general. Chia Lin sums up the business of spies and their essential worth to a state at war by saying, "An army without secret agents is exactly like a man without eyes and ears."
It seems logical to suggest that relating a discussion of secret agents to the economic costs of waging a war may have been tied to criticisms. Some may have believed the employment of secret agents was a waste of time and resources, with outcomes that were vague, hidden, or very difficult to assess in quantitative terms. However, Sun Tzu repeatedly reiterates the far more important need to establish long-term goals, especially those that are not immediately realized by any single event.