Military Communication in Feudal Japan - Audible Signals

Audible Signals

Every culture has used drums, horns, or other audible signals to announce the call to battle, to set marching pace, and for a number of other basic commands. Before the age of radios, telephones, and computers, this was more or less the only way to issue orders to a large group of people.

• Taiko are large Japanese drums which, in addition to their military applications, are very common elements in rituals and matsuri (festivals). In war, taiko would be used to rouse the troops, calling them to battle, as well as to summon allies onto the field, to set marching pace, and to encourage troops as they approached victory.

• Horagai were conch shells used as trumpets or horns, to issue orders across the battlefield. A complex system of conch calls came into use by the height of the Sengoku period. Many yamabushi were renowned for their skill with a conch, and were hired into feudal armies as kai yaku, or trumpeters.

Gongs and bells were often used for related purposes, though these were rarely brought onto the battlefield. Rather, they would be kept at camp, and used primarily to rouse the army to battle, and to signal warnings of approaching enemies and the like. It is rumored that in Uesugi Kenshin's war camp, the first bell meant to stop eating, the second to put on armor, and the third to move out onto the battlefield. Much like the Buddhist temple bells used for the same purpose in the Genpei War, later 'war bells' were bronze, and fairly large; they would be stuck by a wooden hammer from the outside, not by a clapper on the inside like Western bells.

Other devices, such as wooden clappers (hyoshigi) were sometimes used in urban war camps, or urban skirmishes, to set time and encourage troops. But the range of their sound is quite limited, and thus so was their use on larger battlefields.