The violent reputation of the ninja has spread throughout the world. Historical records of ninjas as both assassins and mercenaries have built up an image of feared warriors. Several stories, however, passed down as ninja chronicles, reveal the multi-faceted application of ninjutsu. The incorporation of cultural pursuits, religious practices, meteorology, astronomy, and breathing into their training gave ninjas a flexible and creative approach to everyday problems. Ninjutsu, trained correctly, provided a way of life, not simply a way to wage war. The ability of the ninja to use their environment to their advantage, no matter how unfamiliar or challenging, added to their mythical status.
Ninjas hired by the Takeda family used their skills in ninjutsu for the exploitation of mines. Training in physics and mathematics, facilitated by an uncanny sense of direction, allowed the ninjas to extract gold coins from the Takeda family mines. Then, unsatisfied with the harvest, they also extracted quartz and crystal from the same rocks. Afterward, the precious stones became a staple commodity of the province, increasing the standard of living for the whole clan. Through their ingenuity, the ninjas used knowledge designed to increase their expertise in warfare for everyday activities.
Similarly, the ninjas used ninjutsu teachings to control water courses. Using their techniques, they created the Shingen-tei dam on the Kamanashi River. The ninjas created several gaps along the flanks of the Shingen-tei dam to allow water to overflow should a flood occur. Another, smaller dam outside the first created a cascade effect that helped disperse the overflowing water. The whole system allowed the dam to hold firm against flooding without risking a rupture. The men working alongside the ninjas were awed by their ability to control nature itself with ease. While control of water could create a powerful weapon in war when combined with strategic foresight, the ability to create durable dams also had great economic benefits in times of peace.
The subtler skillsets of the ninja came to the fore during the relatively peaceful reign of Tokagawa Ieyasu. No longer needed as mercenary units on the battlefields, the ninja began serving the shogunate as informants. Stealth and cleaver disguises allowed the ninjas to infiltrate the households of feudal lords and peasant homes alike. By blending into the surroundings, they could learn of treachery before it could become a threat to the shogunate. The intricate web of ninja informants contributed immensely to the decades of stability following Ieyasu’s ascension to power.
The ninjas’ physical capabilities set them apart from other contemporary warriors and carved their reputation as fighters into the annual of history. Yet their tough exteriors harbored more refined abilities that extended beyond the battlefield. From predicting the weather to changing the course of rivers, the ninja could interact and understand their environment in ways others of the time could not. Combined with an adaptable and pragmatic attitude, their diverse education and training system allowed ninjas to surmount any obstacle placed in their path.