For a background behind Hyperart, please see https://fabyeareat.wordpress.com/2014/06/17/shinjuku-station-hyperart-thomasson/ Continue reading
The name Shinjuku Station is a misnomer. It should be named Shinjuku Stations. There are 2 ends to the station for 2 sets of different Metro lines and the walk between them is quite a distance. It also serves the local train lines, regional train lines and JR lines which cross all over Japan. You would expect the various lines would be served by duopolies in most countries at best but in Japan, many lines are owned by different companies.