Ninja Codes and Colored Rice - the History of Goshikimai

Susan - every other Sunday

During the medieval age, ninjas—(also called shinobi)—were known and feared throughout Japan for their skills as spies and assassins. 

Sneaky, sneaky.

Most people know ninjas only from Hollywood movies, where men in black pajamas appear out of nowhere, throw a shuriken or two, and disappear in a cloud of smoke. In reality, ninjas did far more than assassinate unsuspecting victims (though they did their share of that as well) and they developed a remarkable arsenal of tools to aid them with every aspect of medieval espionage.

All ninjas trained in combat skills, but many were not primarily assassins. Far more often, the shinobi acted as spies and undercover agents, gathering information for their clans or for samurai who hired them to spy on rival warlords. 

No one suspects the man with a basket on his head.

Note: in medieval Japan, a group of itinerant monks (called komuso) who followed the Fuke school of Zen Buddhism did, in fact, wander the roads with baskets on their heads.  The baskets were intended to help them separate themselves from the world--and also made convenient disguises for ninjas hoping to pass on the roads unnoticed.

In order to pass information to other agents, the shinobi developed several systems of passing secret information, known as “dentatsu-jutsu.”

One of these secret methods of communication, known as goshikimai, involved an elaborate code and grains of dyed or colored rice. 

Colored rice in bamboo tubes. Text messaging, medieval style.

Shinobi (or their female counterparts, called kunoichi) dyed or painted grains of rice in five different colors: purple, black, red, yellow, and blue. 

Different combinations of colored grains represented the various phonetic sounds of the Japanese language. When combined, the sounds formed words and messages which other ninja spies could understand.

Memorize this and you're ready to go.

The colored rice was left by roadsides or in other pre-arranged locations--generally outside, where colored rice was less likely to draw attention (though, between you and me, I'm not sure bright red rice would ever fail to draw a glance). 

Birds and animals left the rice alone because the dye, which was also water-resistant, was designed to taste unpleasant. Even so, rice breaks down quickly in Japan's humid climate, making goshikimai an effective short-term method of secret communication. Once received, the messages were normally scattered and left to decompose naturally, under a bush or in a river, leaving no trace of the message and no evidence for the recipient to carry away from the scene.

I haven’t yet had the chance to use goshikimai in my novels, but it has a scheduled appearance in an upcoming story. Frankly, it's just too cool to leave out. 

So tell me...what's the coolest ancient or medieval spy tool in your arsenal of knowledge?