Since 1989, Japan and Taiwan have continued to work on a collaborative study on Sabo. On November 9 and 10, 2006, “2006 Ecological Construction International Symposium” which was hosted by the Public Construction Commission of the Executive Yuan, Taiwan, and conducted by Taiwan University, was held in Taipei, Taiwan, and more than 600 participants from governmental organizations, universities, and private sectors attended the symposium. From Japan, Dr. Hideji Maita (Tsukuba Univ.), Dr. Shun Okubo (Japan Sabo Association), and Dr. Nobukazu Nakogoshi(Hiroshima Univ.) were invited to the symposium, and they made presentations about Sabo’s roles in disaster prevention and nature restoration in Japan, commitment to conservation of ecosystem, and the sediment state of rivers with a steep cobbled riverbed.