In this paper it is assumed that equity markets reflect the development of the overall economy of a country. Equity markets, among other factors, are considerably affected by factors such as inflation or deflation. Therefore, when inflationary or deflationary pressures appear, Central Banks try to manage those pressures in order to minimise their impact on the economy. In this paper, the case of Japan will be examined. Japan can be considered an example of a country which was under extended deflationary pressures for about three decades. In this study, the authors investigate different time frames for the Japan equity market. The research is based on Japan equity market (NIKKEI) returns. The authors aim to answer the question of whether the Japanese market complies with the Efficient Market Hypothesis (EMH) for different time frames, as well as test analytically if Japan’s stock market and economy have improved after the implementation of different attempts at Quantitative Easing (QEs), a Zero Interest Rate Policy (ZIRP) or a Negative Interest Rate Policy (NIRP) to curb deflationary impacts on the economy. The analysis and obtained results could be useful for risk and portfolio management, and could be extended to other markets.