What to bring?

Things to bring
Of course, don't forget to bring your pants, shirts, underwear, toothbrush etc.
However, I recommend not buy new things such as sweater etc (if you want to buy, go ahead).
You can buy second hand stuff over here.
e.g rather buying a new 5000~6000yen sweater, you can get used a 1000yen sweater.
After you reach Japan, buying used furniture, used home appliances can save a lots of money.
Trust me, the second hand items over here mostly are in perfect shape ( some items can be categorized as junk too). Some items do come with box and manuals.
Some of the famous second hand shops are Hard-off, 2nd street (Kansai), Ryohin-kaikan (Kansai).

If you have time, go to the flea market. At flea market, they sell new and used items.
The schedule in Kanto area is here and in Kansai area is here. I recommend you to go to the flea market at Nissan stadium at Yokohama.