Less than a century after the end of the Nanboku-chō Wars, peace under the relatively weak Ashikaga shogunate was destroyed by the outbreak of the Ōnin War, a roughly ten-year struggle that converted the capital of Kyoto into a battlefield and a heavily fortified city that suffered severe destruction.
A great many developments and significant events took place during this period, ranging from advances in castle design to the advent of the cavalry charge, the further development of campaign strategies on a grand scale, and the significant changes brought on by the introduction of firearms.