Imagine you borrowed $1 mil from the yakuza and in order to pay the debt you borrowed money from, say, an Italian mafiozi. Then you 'somehow' spend a weekend in Las Vegas and now you don't have any money. The only thing that is left is your house. Now both the mafiozi and yakuza come to your house and start arguing who's going to take it. Your continued well being is the last thing those two are worried about.