Final answer:
The Kamakura shoguns successfully repelled Mongol invasions due to strategically built fortifications and the divine winds or 'kamikaze'. Their efficient governance system and strong military force, which included the samurai following the bushi code, played a significant role in protecting Japan.
Step-by-step explanation:
The Kamakura shoguns were successful in repelling the Mongol invasions primarily due to several strategic and environmental factors. During the first invasion in 1274, after intense fighting, a powerful storm, believed by many to have been a divine wind or 'kamikaze', helped to repel the Mongol forces. Anticipating a second attempt, the ruling Hojo clan prepared by building extensive land- and sea-based fortifications to better defend against future attacks. In 1281, the Mongols returned, and once again, a typhoon struck, leading to a belief that the gods were protecting Japan. This event further reinforced the military reputation of the Kamakura shogunate and its samurai warriors.
The Kamakura period is marked by strategic governance and self-imposed isolation, which ultimately helped in maintaining Japan's sovereignty against foreign incursions. The shogunate, strengthened after defeating Emperor Go-Toba's attempt to regain control, relied on samurai and their adherence to the bushi code to defend the nation. Additionally, the shoguns' strategy to appoint stewards as a decentralized form of governance ensured sufficient peace and loyalty required to muster a strong military response against any invasion.
Furthermore, the Kamakura shoguns did not greatly expand their jurisdiction, but made effective use of their existing legal system to rule efficiently. This approach, which included a preference for personal dispute resolution and minimal bureaucratic paperwork, also contributed to stronger local governance, capable of rapid and coordinated action in times of foreign threats like the Mongol invasions.