The conflicts occurred across the Japanese archipelago, especially Honshu, Kyushu, and Shikoku, with the Boshin War extending north to Hokkaido. Kyoto and the surrounding region were important in contests over imperial and shogunal authority, while Edo, now Tokyo, became a later political center. Battles also involved provincial castles, coastal strongholds, and naval routes through the Inland Sea. Japan's mountainous terrain, narrow agricultural plains, and separation into islands shaped regional power and military movement.