Why was there no central government in japan from 1300s to the 1500s

There are two reasons for this. In the first place, there was constant warfare among the powerful regional feudal lords, the daimyos, who vied for power and influence. This debilitated any central authority. The feudal clans managed big armies of samurais (warriors). The other reason is the symbolic role played by the emperor. He was deemed as a living deity, but he had little effective political power. This status quo lasted until the early 17th century when the powerful Tokugawa clan managed to defeat its rivals and impose military and political unity over the whole Japanese territory.

the group i'm selecting: greeks.

a first group of greek immigrants came to the us in the 1850s. the second group came to america starting in the 1890s due to economic opportunities they didn't have back in their home caused by the hardships of ottoman rule. greek immigration was 90% male, many of them expected to work and return to greece after earning enough capital, but ultimately had to remain in the us after the greek genocide.