In Feudal Japan, which social class had the most political power?

Under which 16th century Japanese Daimyo (Lord) did Japan undertake its first formal trade relations, as well as cultural exchanges, with Europe?

What is the name for the period of constant civil war and social turmoil that occurred during 16th Japan?

What position, appointed by the Shogun was akin to a magistrate, which was responsible for either the running of a large city, a government department, or a region?

The Sengoku Period in Japan lasted from __________________.

What Japanese military class followed the code known as bushidō and was somewhat related to European concepts of chivalry?