Tenshō Iga War

Timeline

1. 1579Mountain passes at the entrances to Iga Province · Iga ProvinceOda Nobukatsu (Kitabatake Nobukatsu), without his father Oda Nobunaga's permission, led some 10,000 men into Iga Province. The Iga Sōkoku Ikki (a league of local lords centered on the ninja bands) used mountain terrain and guerrilla tactics to rout the invading force. Nobunaga was furious on learning of this, harshly rebuked Nobukatsu, and resolved to personally organize a large-scale retaliatory campaign.
2. 1581Azuchi Castle (Oda Nobunaga's headquarters) · Ōmi ProvinceOda Nobunaga carefully planned the second campaign against Iga from Azuchi Castle, mobilizing an estimated 40,000–46,000 men in six columns (roku-dō no gun) attacking simultaneously from Yamato, Ise, Koga and other directions. Nobunaga assigned Oda Nobukatsu to one column to erase his earlier disgrace; the others were led by senior retainers such as Niwa Nagahoshi and Tsutsui Junkei. The strategy aimed to seal all of Iga's escape routes, leaving no room for flight or outside aid.
3. 1581Various places in Iga Province · Iga ProvinceThe Oda army's six columns entered Iga within about ten days, engaging the Iga ninja bands in fierce mountain fighting. The Iga men resisted stubbornly behind rugged terrain but could not hold out against overwhelming numbers. The Oda forces carried out large-scale massacres of resisters, burning many temples and settlements. According to historical records, casualties were heavy and Iga Province was nearly cleansed; Oda Nobunaga personally toured Iga and rewarded his officers and men.
4. 1581–1582Iga Province and surrounding domains · JapanAfter Iga Province was fully occupied by the Oda clan, Oda Nobukatsu was appointed its lord. Large numbers of surviving Iga ninja were forced into exile: some hid in the Kii Mountains, others eventually entered Tokugawa Ieyasu's service, becoming the core source of the 'Iga-mono' later used by the Tokugawa shogunate. After the Honnō-ji Incident of 1582, Oda Nobunaga died suddenly and the Oda clan's order collapsed, allowing remnant Iga forces to resume activity; but the organizational form of the Iga Sōkoku Ikki no longer existed, and Iga ninja history entered a new phase of dispersal.