It is a rough estimate assuming all other things are equal, but if Japanese households start to invest 20 percent of their financial assets, or about 400 trillion yen, shifting their cash and deposits into equity and investment trusts, at a 1.6 percent dividend yield, this will translate into an annual  8  increase in disposable income of 5 trillion yen, or roughly 2 percent.
Over the last couple of years, the exchange rate has seen large two-way movements with considerable volatility imparted mainly by global spillovers.