"This highlights a broader anti stimulus effect, where the lagging markets globally - UK, Europe and Japan - have been the ones announcing further quantative easing.
"The key will be whether investors have confidence in the long-term outlook for corporate cash flows and profits.
"The Bank of Japan continues to try hard but sadly 2016 has seen weaker global growth, an environment in which Japanese equities tend to lag. Add to this the fact the yen has strengthened - hurting Japanese exporters - and it's seemingly had the opposite effect to what the BoJ wanted."
For Nick Peters, multi-asset portfolio manager at Fidelity International, the effect of the Bank of Japan's monetary policy has been "something of a paradox".
"On the one hand", he says, "the market fell because investors lost conviction in the ability of Abenomics to reflate the economy. However, it would have been a lot worse if Bank of Japan policy had not been so loose.
"The looseness has held yen strength in check and played a preventative role in holding back bigger stock market falls this year."