Hi Geokit and welcome to the forum.
360.000 yen is more than enough for daily expenses. The average salary in Tokyo is about 250.000 yen and I know some Japanese who survive on 150.000 yen a month.
I spend about 20.000 yen/month on food, exluding restaurants (but including take-away bento). Food is very cheap in Tokyo compared to Paris or London. It's easy to eat in a restaurant for an average of 800 yen (from 500 to 1000+ for anything like ramen, pasta, chinese, tendon/katsudon/magurodon, etc.).
The only problem is for accommodation. If you only stay a year, you won't be able to rent a normal flat/apartment as you'll have to buy all the furniture, pay about 5 month deposit, "reikin", etc. and contracts are for 2 years minimum.
So, you can either rent a "monthly mansion" (furnished apartement) for about 130.000yen a month in central Tokyo or stay at a "gaijin house" : good point it's cheap (from 40.000 shared room or 70.000 private room), they usually have free internet and satelite TV and you can meet people ; bad point, you'll have to share the kitchen and bathroom and it can be noisy in some.
I suggest that you should have a look at my site to have an idea of what's available on the market for both monthly/weekly mansions and gaijin houses.
check here