A new bulletin from the OpenNet Initiative (a research partnership of the Citizen Lab, the Berkman Center, and the Advanced Network Research Group) peels back some of the layers of Internet censorship in China. ONI researchers conducted a probe of the filtering practices of the two most popular search engines in China, Baidu.com and Yisou.com, and found a complex matrix of content-blocking that extends beyond filtering search results. In searching for various combinations of the words "free" and "Tibet," the study reveals that certain searches found no results while others do lead to websites, most of which are then blocked through upstream filtering. This initial study sheds some light on what might be the most advanced regime of Internet filtering.