In large part, overseas. Japan has long been known for what's called "the carry trade". This is where you borrow money at whatever ridiculously low rate is avai

In large part, overseas. Japan has long been known for what's called "the carry trade". This is where you borrow money at whatever ridiculously low rate is available in your jurisdiction (e.g. Japan) and then "carry" it to somewhere that has a higher interest rate and invest it there. You then pocket the difference (or spread). I hasten to add that this is due to low interest rates rather than inflation, but guess how we wound up with low rates. The deflation Japan has been suffering from directly arises from the expectation that prices will be lower tomorrow compared to today. So why spend? Invest it somewhere instead. This carry trade stuff has really screwed with a number of exchange rates relative to the Yen and has been going on for a long time.