yesterday (28 aug 2015), bloomberg featured a story about CIS, a japanese daytrader who made $34 million during the recent worldwide stock market volatility (click here: While Many Panicked, Japanese Trader Made $34 Million). a google search about CIS will yield other stories, this one about his trades in 2013 (click here: Mystery Man Moving Japan Made More Than 1 Million Trades).
Frank Zorilla of the blog ZorTrades wrote this article in 2014 about CIS which i think is not only for day traders but is also relevant for traders of all types (click here: 8 Things To Learn From Japan's Biggest Day Trader)