I respect Zzzz1's opinion on this subject because he has actual real world international trading experience in many markets. That being said, why is everyone so negative on the potential of day trading Japanese stocks??? There must be some details that I am missing.
A few years ago I spent a few days taking at look daytrading Japanese Stocks. One of the interesting things that happens is the daily break, "lunch break???". The market closes for one hour and then reopens. What I found is movements in the last few minutes of trading that were far from being normally distributed.
The stock could go down violently before lunch break and then gap up high in the opposite direction, some would continue on in a negative fashion. I actually saw promising predictive results (better than coin flip) using a binary Markov Chain to analyze movements before and after the break. There seems to be violent burst of movement in some stocks then things go quiet for the rest of the day.
http://stocks.finance.yahoo.co.jp/stocks/chart/?code=8783.T&ct=b
Japanese stocks are clearly a different animal, I don't doubt what Zzzz1 is saying but is there any type of advantage to be had? Tape Reading? Momentum? Pairs Trading? ADR Plays for dual listed stocks (e.x. Toyota)? It would be nice to trade a market without constant HFTs picking people off...I would like to think a human could still do that in Japan