The writings of Chikamatsu Shigenori relate a shinobi tradition of utilizing ‘runners’ (Tsugi Hikyaku) for the relay of critical information from place to place.
Before understanding how the principle of this tradition can be useful for those of the modern world, we must understand the context connected with this tradition.
During the Sengoku Jidai of medieval Japan, it was quite common that regions were fractiously fragmented as power shifted from clan to clan; family to family. With so many influential powers vying for the seat of ubiquitous control, it was essential to keep an ear to the activities of neighboring provinces so as to be better prepared to make a decision respecting troop movements or dissolving alliances. For example, the brother of Kimura Yasutaka (the ninja master of Koka who had taught Shigenori the Koka traditions) known as Kimura Kogoemon, while serving the Owari-Tokugawa clan, reported to his lord on a potential insurrection of the Mt. Koya region in 1692. The intelligence report which was allegedly provided by a still existing Koka network was to inform his lord on whether to send troops into the region or determine if the rebellion would be bolstered by more ronin, thus communicating the development of a real problem.
Before the advent of fiber-optic cables and satellite systems, information concerning distant lands was acquired by the five-senses of a spy; a shinobi. Once acquired, the information would not typically be transmitted at the speed of light (though smoke and fire-signals were used), but rather the speed of a horse or human being, and sometimes, the speed of a loosed arrow.
The ninjutsu tradition of using tsugi hikyaku then, incorporated the use of commoners (peasant folk) to transmit messages from enemy provinces or even allied territories. The relay would be comprised of messengers who were separated at intervals and would operate under the guise that they were communicating market prices of goods between provinces. If they were stopped and questioned, their intentions were well-hidden and the real message was preserved.
In a modern world replete with information technology, it is exceedingly easy to send messages far across the planet in the blink of an eye. However while this capability is convenient, it carries with it a certain amount of security risk. One should just well assume that any electronic transmission of any type of information is logged somewhere or a means of breaching the security of these electronic mediums exist. Therefore if one wanted to transmit information across great distances without arousing suspicion or leaving a virtual record of the message and maintain the highest level of information security, it is useful to resort to pre-modern intelligence methods such as the use of relay runners.
Now as is the case with any message verbally communicated between parties, the message may be subject to the frailties of human subjectivity. Ever play the telephone game? If so then at one time you have experienced how messages can break-down and lose resemblance to the original. With this understanding it becomes apparent that the messengers are loyal and precisely check the information they receive.
In such a low-tech system, how fast could we have expected a message to travel between runners? As sourced in my book, the most physically adept of shinobi were reported to have been able to travel 70 miles on foot in a single day.
So we must assume that shinobi messengers if not common messengers were relatively fit.
More to come.