On the 10th day of every month, Junsuke Senoguchi has just one thing on his mind -- the closing level of the Nikkei 225 Stock Average. That's because Mr Senoguchi, an unassuming man in his late forties, has built a machine that's been predicting the direction of Japanese shares, and once a month he gets a progress report on its success. The model makes a simple call -- whether the equity index will be higher or lower after 30 days -- and over almost four years it's been right 68% of the time. "I'm so happy when it works", said Mr Senoguchi, a senior equity strategist at Mitsubishi UFJ Morgan Stanley Securities in Tokyo. "It's because I feel I can predict the future." Algorithms have invaded global share markets, used by everyone from high-frequency traders closing bets in fractions of a second, to specialist asset managers whose strategies are determined by complex quantitative analysis.