I use font called Nanum Gothic for my blog. It's actually korean font but it also have nice japanese font view. I believe nowadays our internet connection is really fast so you don't have any difficulty to reload my blog with this custom font I also don't activate the extra bold style to make my blog faster.
More about the font from Google Fonts page :
Nanum Gothic is a contemporary sans-serif typeface with a warm touch, and it is expertly hinted for screen use. It is part of the Nanum fonts (나눔글꼴) – a set of high quality Unicode fonts designed especially for the Korean-language script “Hangeul” that also support Latin. Designed by Sandoll Communications (산돌 커뮤니케이션) and Fontrix (폰트릭스,) and published by Naver (네이버.)