三方原之戰
Encouraged by his victory over the Tokugawa at the Battle of Mikatagahara in neighboring Tōtōmi Province, Takeda Shingen decided to push farther into Mikawa Province, hopefully opening a route to the capital, Kyoto. Leading a mixed cavalry and infantry force of 30,000 men, Shingen skirted the northern shore of Lake Hamana before advancing inland into Mikawa. His route was opposed by approximately 500 defenders of Noda Castle, situated on the Toyokawa river, commanded by Suganuma Sadamichi. Shingen was confident in his strength of numbers, and in his knowledge that the Tokugawa forces were overextended in various campaigns. Furthermore, his forces had taken Noda Castle with ease during a reconnaissance-in-force two years earlier.