The latest Neilsen Net Ratings in Japan shows that Yahoo Japan still has a commanding lead in search
[netratings.co.jp] [Japanese article]. The 2nd column shows the search reach %. We have Yahoo Japan at 81.1% and Google at 56.2%.
One surprise I noticed from this chart was that Naver is beating Baidu. Those are the two Asian foreign powers trying to break into the Japanese market. I guess they still have quite a way to go.