Sabotage

Arson was the primary form of sabotage practiced by the ninja, who targeted castles and camps.

The 16th century diary of abbot Eishun (Tamon-in Nikki) at Tamon-in monastery in Kōfuku-ji describes an arson attack on a castle by men of the Iga clans.

"This morning, the sixth day of the 11th month of Tembun 10, the Iga-shu entered Kasagi castle in secret and set fire to a few of the priests' quarters. They also set fire to outbuildings in various places inside the San-no-maru. They captured the Ichi-no-maru (inner bailey) and the Ni-no-maru."^[47]

—_{Entry: 26th day of the 11th month of the 10th Year of Tenbun(1541)}

In 1558, Rokkaku Yoshitaka employed a team of ninja to set fire to Sawayama Castle. A chunin captain led a force of forty-eight ninja into the castle by means of deception. In a technique dubbed bakemono-jutsu ("ghost technique"), his men stole a lantern bearing the enemy's family crest (mon), and proceeded to make replicas with the same mon. By wielding these lanterns, they were allowed to enter the castle without a fight. Once inside, the ninjas set fire to the castle, and Yoshitaka's army would later emerge victorious.^[48] The mercenary nature of the shinobi is demonstrated in another arson attack soon after the burning of Sawayama Castle. In 1561, commanders acting underKizawa Nagamasa hired three Iga ninja of genin rank to assist the conquest of a fortress in Maibara. Rokakku Yoshitaka, the same man who had hired Iga ninja just years earlier, was the fortress holder — and target of attack. The Asai Sandaiki writes of their plans: "We employed shinobi-no-mono of Iga. ...They were contracted to set fire to the castle".^[49] However, the mercenary shinobi were unwilling to take commands. When the fire attack did not begin as scheduled, the Iga men told the commanders, who were not from the region, that they could not possibly understand the tactics of the shinobi. They then threatened to abandon the operation if they were not allowed to act on their own strategy. The fire was eventually set, allowing Nagamasa's army to capture the fortress in a chaotic rush.^[49]