Work as a security guard or watchman is rather simple, observe the environment and report if anything is amiss or out of place.
Skills of observation and memory are key to serving well as a security guard, for if you lack these essential skills, one might get the better of you by breaking in, stealing, or otherwise manipulating personnel to gain access to what they seek. On this note, of manipulation, it should be pointed out that the very function of a security guard or watchman, particularly that of observation, can be exploited for malicious or deviant purposes.
Tendo Chido Narai is a chapter of the Shoninki which offers insight as to how this might occur.1 Natori explains therein, among other things, that shinobi should possess a high level of skill in swaying the observation of sentinels or general onlookers up toward the sky, or down low, depending on the target of surreptitious entry.
For example, say one desired to enter a highly guarded area by way of a tunnel intrinsic to the facility, but it tends to be guarded, at least tenuously, by foot patrols. To insure the plan to enter in such a way, the infiltrator might implement a strange display of lights (say fireworks, a holographic projector, or a fleet of Chinese floating lanterns, etc.) in the sky to direct the attention of the guards away from the path of entry and towards the heavens, for the show of lights above is indeed something strange and anomalous to take note of. Only the seasoned or astute sentinel would question whether such a ploy was indeed meant to distract from potential gaps in the secured perimeter.
Likewise, if one desired to enter from above, say a roof, the intelligent infiltrator would employ a distraction on the ground below. There are many ruses that one can think of that might suffice a particular situation. A partner could feign a heart attack or sudden onset of illness, perhaps even rudely argue with a doorman to make a scene, meanwhile the infiltrator would enjoy the convenience of entering the facility by a window or other roof-bound entrance while security is distracted.
Gifted social engineers and common crooks alike might employ the principle of swaying attention to the heavens or to the earth, so it is important that the discipline of a security guard or watchman is such that there is awareness of his/her own weaknesses. It is truly remarkable how the very function of security can make the defended area insecure.
- Cummins, A. & Minami, Y. (2011). The True Path of the Ninja. Tuttle Publishing. p.98