From Bloomberg Market Concept (BMC), in 2013, Japan is traditionally a heavy exporter, especially automobiles. When the yen being weakened, the Japanese automobile being more attractive because it seems to be cheaper to the target market.BMC also documented that "The automobile won more order as a result, so the stock market went up."
Why the stock market went up, is it because investors optimistically value these firms because of better performance? And the result seems to be triggered by the reduction in the value of the yen compared to USD, so the stock market went up, but whether the Japanese stock market still went up if the stock price being calculated in USD?