The tuna auction observation area of the Tsukiji Market will be temporarily closed to visitors to help ensure greater safety and efficiency for those working over the busy New Year season. The auction will be temporarily off limits between December 1, 2011 and January 21, 2012.
Tours will resume on January 23, 2012.
http://www.tourism.metro.tokyo.jp/english/administration/h23/tsukiji_201111.html