Will this affects price?
GMO is a Japanese trading platform for Forex, Equities, Stocks and now Bitcoin, it is insured for hacker attacks and regulated by Japanese Financial Services Agency
This is a good news for Bitcoin community . Definitely this will have an effect to bitcoin price. I believe we can see an increase in price right after this big exchange opened. The reason is that there will be new user and adopter of bitcoin that will flock in to this exchange. Aside from that I am sure this big exchange have marketing and promotional strategy to entice new to bitcoin to open up and get involved in bitcoin trading.