Genjyou Kaifuku - Restoration

原状回復 (Genjyou Kaifuku) Restoration to original condition. This is the standard that owners hold their properties to in Japan, but doesn't mean "brand new." 

By law, when you rent a property in Japan you sign an agreement which means you are responsible for paying for any of these fees required to restore the property back to the condition it was before your tenancy. BUT this is only when the property is damaged beyond what is considered "daily use." 

So as long as you don't damage the property on purpose or negligently (aka there are just the scuffs and marks from daily use) then it's the owner's responsibility to pay for these. 

Potential cost

However should you be in the position where things are damaged and you do have to pay to replace or repair things, how much could you expect to be charged?

You will always be expected to pay the cleaning fee when you move out of your apartment. This is the cost to have the apartment professionally cleaned, it doesn't matter how good a job you've done cleaning it yourself the owner will still have the place professionally cleaned when you leave. This could cost anything from 30,000 yen upwards! The bigger the apartment the more expensive the cleaning fee. 

Things like tatami will cost at least 5,000 a mat to replace and they will normally replace all not just one at a time! Same with sliding doors 10,000 yen or more for a pair. Wallpaper depends on the size of the area they want to replace but can cost from 1,500 yen per meter squared. 

You should avoid smoking tobacco, etc. Inside your apartment as the owner can say "everything stinks like tobacco!" and charge you to replace everything in the apartment! So just be wary of not causing damage to the apartment and save yourself some hefty fees!