One of the major SEM tools all over the world is Kenshoo. They have released an interesting article about Asian PPC market. Global Search Trends infographics
Asia Pacific Region (Kenshoo calls APJ which means Asia Pacific and Japan. Some companies like Kenshoo who focuses on Japanese market call like this) has been increasing that is 28% UP on YoY (2012 vs. 2013) and 16% UP on Quarterly basis(Q3 2013 vs. Q4 2013). Especially mobile ads have been doing well in Japan.
Some people say Japan is already mature market. Yes it’s true. As you can see above, there is a huge room to invest in Japan. As we’re expecting something new to invest money, as long as your product is attractive and fully localized in Japanese, you’ll have a chance to get market share in Japan.