The reasoning behind BOJ's move was to force banks to actually lend some money to people* Getting funding to start a business in Japan is rather hard. The good

The reasoning behind BOJ's move was to force banks to actually lend some money to people* Getting funding to start a business in Japan is rather hard. The good old fashioned way was to get a loan from the bank. Japanese banks simply prefer to avoid risk at all costs, deposit a pile of cash with BOJ and collect almost 0 interest :) Better than those risky loans. * and of course it doesn't hurt to weaken the currency while at it. Everyone and their dog are doing this and it is getting really hard to be the one weakening the currency the hardest.