The Sengoku period is the period in Japanese history in which civil wars and social upheavals took place almost continuously in the 15th and 16th centuries. Though the Ōnin War is generally chosen as the Sengoku period's start date, there are many competing historiographies for its end date, ranging from 1568, the date of Oda Nobunaga's march on Kyoto, to the suppression of the Shimabara Rebellion in 1638, deep into what is traditionally considered the Edo period. Regardless of the dates chosen, the Sengoku period overlaps substantially with the Muromachi period .