Editing Ninja (section)

==Roles==
In his ''Buke Myōmokushō'', military historian Hanawa Hokinoichi writes of the ninja:

{{blockquote|They travelled in disguise to other territories to judge the situation of the enemy, they would inveigle their way into the midst of the enemy to discover gaps, and enter enemy castles to set them on fire, and carried out assassinations, arriving in secret.}}

===Espionage===
Espionage was the chief role of the ninja. With the aid of disguises, the ninja gathered information on enemy terrain and building specifications, as well as obtaining passwords and communiques. The aforementioned supplement to the ''Nochi Kagami'' briefly describes the ninja's role in espionage:

{{blockquote|Concerning ninja, they were said to be from Iga and Kōga, and went freely into enemy castles in secret. They observed hidden things, and were taken as being friends.}}

Later in history, the Kōga ninja would become regarded as agents of the [[Tokugawa clan|Tokugawa]] ''[[Shogun#Shogunate|bakufu]]'', at a time when the ''bakufu'' used the ninja in an intelligence network to monitor regional ''daimyōs'' as well as the [[Imperial Court in Kyoto|Imperial court]].<ref name="ratti 1991 327" />

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

The ''Tamon-in Nikki'' (16th century)—a diary written by abbot Eishun of [[Kōfuku-ji]] temple—describes an arson attack on a castle by men of the Iga clans.

{{blockquote|This morning, the sixth day of the 11th month of [[Tenbun]] 10 [1541], 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 [[Motte-and-bailey castle|bailey]]) and the ''ni-no-maru'' (second bailey).}}

In 1558, [[Rokkaku Yoshikata]] employed a team of ninja to set fire to [[Sawayama Castle]]. A ''chūnin'' captain led a force of 48 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 (emblem)|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 ninja set fire to the castle, and Yoshitaka's army would later emerge victorious. The mercenary nature of the ''shinobi'' is demonstrated in another arson attack soon after the burning of Sawayama Castle. In 1561, commanders acting under [[Kizawa Nagamasa]] hired three Iga ninja of ''genin'' rank to assist the conquest of a fortress in [[Maibara, Shiga|Maibara]]. Rokkaku 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". 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.

===Countermeasures===
A variety of countermeasures were taken to prevent the activities of the ninja. Precautions were often taken against assassinations, such as weapons concealed in the lavatory, or under a removable floorboard. Buildings were constructed with traps and trip wires attached to alarm bells.<ref name="draeger smith 1981 128-129">{{Harvnb|Draeger|Smith|1981|pp=128–129}}</ref>

Japanese castles were designed to be difficult to navigate, with winding routes leading to the inner compound. Blind spots and holes in walls provided constant surveillance of these labyrinthine paths, as exemplified in [[Himeji Castle]]. [[Nijō Castle]] in [[Kyoto]] is constructed with long [[Nightingale floor|"nightingale" floors]], which rested on metal hinges (''uguisu-bari'') specifically designed to squeak loudly when walked over. Grounds covered with [[gravel]] also provided early notice of unwanted intruders, and segregated buildings allowed fires to be better contained.<ref name="fieve 2003 116">{{Harvnb|Fiévé|Waley|2003|p=116}}</ref>