USD/Yen since QQE with negative interest rate

Besides raising stock prices, the main idea behind QQE with a negative interest rate was to further weaken the Yen.

This effect could not be seen since the Introduction of QQE with a negative interest rate.
It is assumed that because of the "risk-off mode" of global investors demand for the "safe haven" Yen has increased, leading to an appreciation of the yen.