This paper reviews the Bank of Japan’s (BOJ) monetary policy from the perspective of surprise observed in the foreign exchange market and investigates the potential of central bank’s surprising announcement as a policy tool to change people’s deflationary mindset. We propose a surprise measure that is based on the daily candlestick-chart data on the yen-dollar exchange rate and identify surprise that occurred in the Tokyo and New York markets. Using the identified surprise, we evaluate monetary policies of BOJ governors and compare them with those of Fed chairs. We present statistical evidence that shows that under the command of Governor Haruhiko Kuroda, the BOJ was strongly dependent on surprise policy in the course of the quantitative and qualitative monetary easing. We also show that the surprise generated during the Kuroda term succeeded in raising the trend inflation rate, but failed to steepen the slope of the Phillips curve and to enhance the pass-through of the foreign exchange rate.