Here are some analysts' views on the move and market reaction:

SHIGETOSHI KAMADA, GENERAL MANAGER - RESEARCH DEPARTMENT, TACHIBANA SECURITIES, TOKYO

"The outcome was in line with our expectations. It became clearer that the Bank of Japan will continue to be committed to support the economy. The yen fell to 145 yen to the dollar for a moment (after the announcement). Unstable move of the yen increases uncertainties of Japanese stocks. Even as some companies benefit from the weak yen, some suffer as costs increases so in total that is going to be a worry.

"For a while Wall Street move will remain as the main market cue for the Japanese stock market."

HIROAKI MUTO, ECONOMIST, SUMITOMO LIFE INSURANCE CO, TOKYO

"The BOJ was aware that an announcement like this should surely prompt a weak yen beyond 145 per dollar.

"Although the statement says "we must be vigilant at financial, currency market moves", looking at how the BOJ communicates, it doesn't seem they are seriously mindful of that. They might be thinking a weak yen beyond 145 level is not a bad thing that will bring negative impacts to the economy."

(Reporting by Junko Fujita; Compiled by Rashmi Aich)