Tatami replacement cost

Hi. I...have a question that probably can't be answered, but I need to ask anyway. I am an English teacher living in Yamaguchi-ken, and I will soon be leaving. A few days ago, only a couple of months before I leave, I had a massive accident with my tatami, leaving sticky, nasty, highly-visible stains across most of the room (four-mat). While my contract is held by the BoE, not me, I have a hunch I may be asked to pay for it, because it is in every way my fault and obvious in that matter.

So...anyway, I'm just wondering how much money I should put aside for the room inspection and subsequent possible tatami replacement. I looked at the bottom of this tatami once, and it's not the solid mat type, just the fibers stretched over half a frame.

Just a ballpark would be nice (ie, 500 dollars or 5000).

Thanks.

It's likely that they are going to replace tatami mats anyway after several years or after a tenant or two, so if the landlord is nice they would not charge "extra" on the spot but just take a bit out of the deposit as part of "normal" cleaning/repair cost.

Per mat, it's something like 8,000 - 12,000 yen (depending on exactly what they do - if they just change the top sheet or the whole thing, etc.), so even if they decided that it's time to change the whole 4-mat room and stick the bill with you, it would be around 40,000 yen or so (just taking the average) so we're talking about 400 US dollars. The exact price you get from really depends on the grade as well.