13. The Use of Spies
20
Whether the object be to crush an army, to storm a city, or to assassinate an individual, it is always necessary to begin by finding out the names of the attendants, the aides-de-camp, #
Literally "visitors", is equivalent, as Tu Yu says, to "those whose duty it is to keep the general supplied with information," which naturally necessitates frequent interviews with him.
and door-keepers and sentries of the general in command. Our spies must be commissioned to ascertain these. #
As the first step, no doubt towards finding out if any of these important functionaries can be won over by bribery.