Battle of Okazaki Castle (Ōkawahara)

Timeline

1. 1560–1561Mikawa Province · Aichi PrefectureAfter Imagawa Yoshimoto's defeat and death at Okehazama, Matsudaira Motoyori gradually threw off the Imagawa main house's control and formed an alliance with Oda Nobunaga, creating the conditions for a military purge of remaining Imagawa forces in Mikawa Province.
2. 1561Ōkawahara Castle · OkazakiMotoyori led his army to besiege Ōkawahara Castle, held by the Utsunomiya clan, Imagawa vassals. The castle commanded a key point in Mikawa and was an important stronghold of Imagawa influence there; after the assault the Matsudaira forces captured it, further squeezing Imagawa room for maneuver.
3. 1561–1562Mikawa Province · Aichi PrefectureAfter Ōkawahara Castle fell, Matsudaira forces continued clearing out remaining Imagawa remnants in Mikawa, and in 1562 moved into Okazaki Castle, essentially completing control of Mikawa Province and laying the base for a later eastward advance into Suruga and participation in central politics.