Kyushu is the southernmost island of the four big islands Japan consists of. Although the island is a bit isolated with respect the events on Honshu, it is a major point of entry for influences from the outisde world. Kyushu is close to China and Korea and for centuries it was the sole link with the west.
The prime attraction is Nagasaki one of the tow places bombed by Allied forces with a Nuclear bomb. Kagoshima and Kumamoto have interesting castles and gardens. Mt Aso is great for hiking.
In the north Fukuoka / Hakata is the main point of entry. Ferries to Okinawa{ leave from here and the Shikansen trains from Tokyo arrive here.