We present a system that tries to automatically collect and monitor Japanese blog collections that include not only ones made with blog softwares but also ones written as normal web pages. Our approach is based on extraction of date expressions and analysis of HTML documents. Our system also extracts and mines useful information from the collected blog pages. Categories and Subject Descriptors H.5.4 [Information Systems]: Hypertext/Hypermedia; H.3.5 [Information Systems]: Online Information Services General Terms Management Keywords weblog, document analysis, monitoring, text mining, trend analysis