@oboero2 , I understand the conundrum you are in. My suggestion would be the following :
(a) since you are beneficial owner ( even if there is no will ), it would be legally correct for you to file an FBAR using your parent's bank account number -- while this is not required but it is in the spirit of the FBAR requirement. I say also because , no matter which path you follow, the transfer in of the amount to your US bank will raise an SAR ( Suspicious Activity Report ) and then generally nothing happens to it. This way in case of query, you are covered . It is not a tax even.
You al.so said " in my house in Japan " -- does that mean the house of your demised parent or your own house in Japan ? Because when you sell that ( if and when ), you may need to pay capital taxes to USA.
Have I answered your query ( perhaps in a round about way )?
Is there more I can do for you ?
pk
