I am going to Japan for three months long intern ship, so I prepare a list for this trip.
Essentials
passport
suitcase, backpack
air tickets
pens, pencils
papers
insurance card
Financials
credit cards
cash
Clothing
six shirts
5 trousers
2 shorts
2 swimming gears
underwear
Others
Books:
Tupperware food container and cup
Swiss Army knife
Torch
Mobile, although can't use, but I can listen to music.
photos
a plug converter
compass
some medicine
(please refer to http://www.travellerspoint.com/packing-list.cfm for your packing list)