Amakusa can be reached only by road, boat, or plane. There is a single-track railway line ending at Misumi the tip of the peninsula pointing to Amakusa, which consist of two main island. The first smaller is Kami Shima (upper island) 上下島 the second larger is Shimo Shima (lower island)下島. There are 5 bridges to cross from the main island of Kyushu to Amakusa. There is even a sixth bridge to finally cross over to the island capital Hondo at the end of the trip. I have travelled that road many times on the way to visit my wife’s family, these photos are from April 2013. Since then, a new number 1 bridge has been built in parallel to the old one. Also, there is a new additional number 6 bridge in Hondo. I hope that one day I can update on that and post some improved photos. Some information is also available on Wikipedia: https://en.wikipedia.org/wiki/Five_Bridges_of_Amakusa