Yakyuu de Sensou suru Isekai de Choukoukoukyuu Ace ga Jakushou Kokka wo Sukuu Youdesu

Tokonatsu Taichi was a standout pitcher known for his powerful fastball and skillful pitching during a high school baseball tournament. After the game, he died in a bus accident but awoke in another world where wars are settled through baseball matches. He finds himself in the weakest nation, one that has steadily lost territory and population to stronger rivals. The country now faces decline, and Taichi must find a way to reverse its fate through the sport.