Why is the muromachi period considered a fragmented part of japanese history ?

The muromachi period is considered a fragmented part of Japanese history because it is a division of Japanese history running from approximately 1336 to 1573.

the fact that could also be added to column b is that during world war ii, specifically between the years 1941 and 1945, japan expanded its territory towards the indonesian territory in what was known later as part of the "pacific war". in that time, japan could conquer the philipines, singapore,   borneo, central java, malang, cebu, sumatra and various other islands of the area, therefore expanding its territory for a brief period of time.