"Iga-Shu in Muromachi and Sengoku Period - a study from historical materials" (summary)
Lecturer: Shigeru Kobayashi
The people in Iga have been described, not so much as individuals, but as members of groups. "Iga-shu" for example, grouped themselves based on a kin group.
Through some description we gain some insight into "Mansai Jugou Nikki "; they formed some bigger groups in Iga area which were based on the sense of faith in a territorial connection group. Among those are for example Kitakata-clan, Fukuchi-clan and Hioki-clan (so called "Tsuge-sanpo").
In the Sengoku period, they were mobilized as military members by the Daimyo or other lords around them. The number of their mobilized military members was around 100 to 300.
Some historical documents show clearly that their battle strength was quite high and sometimes they could be the major forces in battles to guard the fortresses and so on.
Each Ryoshu (feudal lord) in Iga in the late Middle Ages had a relatively strong sense of independence. It could also be that Ryoshu constantly established master-subordinate relationships with a Daimyo. However, there were around 700 castles only in the Iga area at that time. Due to this fact we can assume that many of them might work as mercenary on each occasion.