As an option I can recommend from myself to read an interesting material about the battle of Nagashino here https://samuraiwr.com/battles/battle-of-nagashino . The Battle of Nagashino was one of the clashes between two powerful samurai clans, Oda and Takeda, and symbolized the struggle for power and territory. By studying this battle, you will be able to understand how the samurai sought to consolidate their position, as well as how military tactics and strategies evolved during that period. This will allow you to delve deeper into the historical context and understand how Japan's destiny was shaped at the time.