User blog comment:BleedingUranium/Soundtrack List!/@comment-27767503-20160209205725/@comment-26843868-20160211093245

Hi there,

I've done some research, and it turns out that "Isshuukan" or "一週間" is the Japanese name for the Russian song "НЕДЕЛЬКА".

I'm not sure why it's not on the soundtrack, but it seems to be the right song.