To get a better understanding of how and why the buildings of Hashima were built, I have recently watched the recent BBC Four season of post war modern architecture. In particular the two part series (Bunkers, Brutalism and Bloodymindedness: Concrete Poetry with Jonathan Meades) gave me a good insight in to the design and the practical function of the Brutalism style of architecture that can be seen on Hashima.
Trellik Tower (1972) is a good example of the Brutalist architectural style.
Image from here: http://www.best-london-attractions.co.uk/trellick-tower.html
Many of the buildings of Hashima date from the 1940’s -1960’s and feature a similar style.
Image from here: http://gakuran.com/gunkanjima-ruins-of-a-forbidden-island/