- 故惟明君賢將能以上智爲間者必成大功此兵之要三軍之所恃而動也
who had served under the Hsia. Likewise, the rise of the Chou dynasty was due to Lü Ya
呂尚 Lü Shang, whose "style" was 子牙，rose to high office under the tyrant 紂辛 Chou Hsin, whom he afterwards helped to overthrow. Popularly known as 太公，a title bestowed on him by Wên Wang, he is said to have composed a treatise on war, erroneously identified with the 六韜.
who had served under the Yin.
There is less precision in the Chinese than I have thought it well to introduce into my translation, and the commentaries on the passage are by no means explicit. But, having regard to the context, we can hardly doubt that Sun Tzŭ is holding up I Chih and Lü Ya as illustrious examples of the converted spy, or something closely analogous. His suggestion is, that the Hsia and Yin dynasties were upset owing to the intimate knowledge of their weaknesses and shortcomings which these former ministers were able to impart to the other side. Mei Yao-ch‘ên appears to resent any such aspersion on these historic names: “I Yin and Lü Ya,” he says, “were not rebels against the Government (非叛於國也). Hsia could not employ the former, hence Yin employed him. Yin could not employ the latter, hence Chou employed him. Their great achievements were all for the good of the people.” Ho Shih is also indignant: 伊呂聖人之耦豈爲人間哉今孫子引之者言五間之用須上智之人如伊呂之才智者可以用間葢重之之辭耳 “How should two divinely inspired men such as I and Lü have acted as common spies? Sun Tzŭ’s mention of them simply means that the proper use of the five classes of spies is a matter which requires men of the highest mental calibre like I and Lü, whose wisdom and capacity qualified them for the task. The above words only emphasise this point.” Ho Shih believes then that the two heroes are mentioned on account of their supposed skill in the use of spies. But this is very weak, as it leaves totally unexplained the significant words 在夏 and 在殷. Capt. Calthrop speaks, rather strangely, of “the province of Yin ... the country of Hsia ... the State of Chu ... the people of Shang.”
27. Hence it is only the enlightened ruler and the wise general who will use the highest intelligence of the army for purposes of spying,
