On the first day of January 1544, Yagyū castle was brimming with secret activity, and it wasn’t just for the New Year’s festivity of O-Shogatsu. That evening Ieyoshi had convened a council with the headmen of his shinobi, the ‘secret men.’ Trained in the art of stealth, their main task was the gathering of information. For a clan the size of the Yagyū, intelligence meant survival. Ever since they had joined Emperor Go-Daigo’s cause, the Yagyū had relied on intelligence rather than brute force to achieve their aims. Go-Daigo’s defeat at Kasagi had taught them an important lesson: it had been the stealth of their night attack rattier than their superior numbers that had made the enemy victorious.
The Yagyū were one of the few clans to have their shinobi. Powerful chieftains simply hired mercenaries to do their dirty work—spying and winning by stealth wasn’t part of their mindset. Proud of their martial prowess, they relished the challenge of testing it in battle and poured their heart in the strength and valor of their armies. The spies they hired were of low stock, shallow, unreliable men who massaged their message to suit their client and were known by a large number of names: rappa, suppa, toppa, dakko, all of them derogatory.
Being only a small clan, the Yagyū knew they had to rely on more than just military might. For almost two centuries now, they had maintained a small force of shinobi. Recruited from local clans, these men of stealth passed their skills on from father to son, forming a large regional network of spies who could be mobilized at the drop of a hat. They had proven their effectiveness in the recent battle for Kasagi-dera when they had helped both to anticipate and trace the attack from Iga.
The Yagyū shinobi had developed skills surpassing those of the average spy. Called ninjutsu, or hidden technique, it was a skill-set that embraced a great variety of disciplines. They were able swimmers, could go on next to no food for days on end, and could climb the steepest walls. To do this they used a so-called uchikugi, a small iron anchor attached to a long rope, which they would hurl over a defense until it caught. Even without it, they were able to scale a castle wall making use of the crevices between even the most tightly laid stones.
Unlike regular warriors, who had just one or two weapons of choice, shinobi used a large range of weapons, including the popular shuriken and makibishi, but also a variety of farm tools like the nata (billhook) and kama (sickle). Their sword was the shinobigatana, long enough to hold its own against the regular katana, short enough to carry on one’s back. Their favorite weapon was the kusarigama, the notorious chain sickle, after the piece of chain that connected the sickle to a small weight. Whipping the weight forward, they could entangle an opponent’s weapon or limb and draw them in to strike with the sickle.
There was a strict hierarchy among the Yagyū shinobi, and each group had its own specialty. The secretive Kitanoyama, who lived among the mountains on the eastern edge of the Yagyū domain and had served them since the very beginning, specialized in teisatsu, reconnaissance. They could make their way into any stronghold and memorize troop numbers, weaponry, down to the place where a harness had been made. Only the teisatsu wore the typical dress of the shinobi, a dark, short-sleeved uwagi tucked into a dark karusan hakama, the hakama with trouser legs, but tapered down to fit tightly around the shins. In winter they would wear warm, padded garments, but never any form of armor. Nor did they wear the regular headgear. Instead, they wore a dark cowl, leaving only their eyes exposed. Their sinister appearance and exceptional ability to disappear soon gave rise to outlandish rumors that spread among a superstitious populace who came to believe shinobi could fly through the air and walk on water. The last one had a kernel of truth, for one of their shinobi had once escaped by staying under water and breathing through a reed.
The Obo, who lived a few miles south along the road to Uda, were different. They had specialized as kanchō, spies who mixed with the troops of hostile clans, thus extracting valuable information on troop movement and influencing morale. The best of them were able to insinuate themselves into the highest ranks, gaining direct insight into an enemy’s strategy. Their’s was one of the most dangerous roles, but also the most valuable.
The Sakahara, whose village lay a few miles down the Yagyū Kaidō toward Nara, had developed a special talent for kakuran, ‘agitation.’ They were masters in stirring up resentment and spreading rumors among the subjects of enemy warlords. They were looked down upon by the other shinobi, but not by the Yagyū chieftain, who knew how to value psychological warfare.
Only the shinobi from Iga and Koka rivaled those of the Yagyit in stealth and subterfuge. Yet, as the recent events at Kasagi had proven, when it came to a pitched battle, the Yagyū warriors amply made up for that.
— Victory Through Endurance, Chapter 2