I've moved several times in Japan, recently I moved out of a apartment I was paying 300,000 a month for. When you move out of a apartment in Tokyo the management company sends a third party inspection company to check on all of the damage you have made and calculate how much of your deposit should be withheld to cover the cost of repairs and cleaning.
I've dealt with these people on several occasions and here is some advice for how they work and how you should handle them.
1) Taking your deposit.
Deposits in Japan are generally 1 month rent, but sometimes can be higher. The idea is that the deposit should cover the apartment fee if you disappear and forgot to pay your rent. Or if you break a bunch of windows on your way out. This is fairly normal in most countries. But in Japan they also charge cleaning fees even if you have cleaned the apartment! How?
2) Cleaning fee's
Japanese apartments usually have a beige wall paper. Every apartment I have stayed in used the same wall paper. If there is a dirt stain on any section of the wall paper, or a scratch on any section, they will charge you to replace the entire section, sometimes the entire wall!!!
3) Japanese floors
All the apartment I have stayed in also use the same floors. They are sectional fake wood panels that can be replaced sections that are about 3x3 feet wide. These floors are very soft and easy to dent or damage. If you damage a small section they will charge you to replace the section
1) How to avoid getting ripped off
When the inspector comes over they will be polite enough but they try to avoid being overly friendly because their goal is to take a bunch of money from you. Don't try to befriend them, it doesn't help at all. I believe they actually receive the fee for repair and cleaning, so they know how much it would truly cost, but they will try to get as much money as possible from you anyway.
Take this inspection very seriously. It has several phases.
Phase 1: Looking at anything that moves, opens, closes or turns on and off to make sure its still working. Windows, aircon, lights. Things like this. This is straight forward. If you broke a door they will find out.
Phase 2: This is where things get ugly. They start looking at the walls and floors for ANY SMALL MARK! Seriously this is the most insane thing in the world. They will put a small piece of colored tape and say something like "oooh, this is going to have to be replaced!" argue every mark! This is a critical phase. You need to follow them around very closely and challenge every piece of tape they put down. They will even put tape of floor things that were slightly damaged before you moved in. You need to make sure to point those things out too. I've learned to walk around with a wet towel, if they point out a stain, I just clean it and said "oh, that's nothing."
I know this can seem a little silly but its critical because it tells the inspector that you know the game and you aren't going to be taken easily! You need to follow them to every room they go to, do not let up.
Phase 3: This is the most annoying. After putting little pieces of tape all over the apartment they will start measuring and calculating how much money it will cost to "replace" all of the walls or flooring you damaged. At the point before they start measuring, they might even tell you its OK to leave, don't leave. Follow them around as they measure and calculate. When they claim they will need to replace all the wall paper for a 100 foot wall because of a 1cm stain, challenge them. What they will do is say "OK its $10 a foot, and this is 100 feet so that is $1000 out of your deposit" so don't let them do it.
After they calculate they should give you a paper that explains how much you owe, if you think its ridiculous challenge it. I once had someone tell me that they needed to replace 600 feet of carpeting because of a 3 inch stain at the costs of $3,000.
Its normal to lose about 1/3 of your deposit for cleaning. Unless you have done some serious damage, challenge anything about that amount.
Other tips; have inspection happen in the late afternoon, say 5 or 6 and don't turn on the lights. Sounds silly but it helps. They will tell you the inspection should take 1 hour, but since you will need to hassle, set aside 3 hours. If you work for a large company and the company pays for the apartment they will send someone to do this for you. Generally the inspectors don't try to rip off corporations, just individual renters.