The NARO-MARCO International Symposium under the theme "Soil Carbon Sequestration - Needs and prospects under the 4 per 1000 initiative" was held on February 28, 2017 at Tsukuba International Congress Center. The symposium aimed to provide a venue to enhance research, research cooperation, and collaboration on soil carbon and greenhouse gas mitigation in agricultural systems across Asian countries and beyond, in conjunction with the 4 per 1000 initiative. The keynote talk was given by Dr. Claire Chenu of the Agro Paris Tech/INRA in France. Other speakers include Dr. Minggang Xu (Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Science), Dr. Suphakarn Luanmanee (Ministry of Agriculture and Cooperatives, Thailand), Dr. Cherukumalli Srinivasa Rao (Indian Council of Agricultural Research-Central Research Institute for Dryland Agriculture, India), Dr. Hideo Kubotera (Central Region Agricultural Research Center, NARO), Dr. Shoji Matsuura (Institute for Agro-Environmental Sciences, NARO), Dr. Yasuhito Shirato (Institute for Agro-Environmental Sciences, NARO), Dr. Jagadeesh Yeluripati (James Hutton Institute, UK), Dr. Akihiko Ito (National Institute for Environmental Studies, Japan), and Dr. Mayumi Yoshimoto (Institute for Agro-Environmental Sciences, NARO). The symposium also aimed to establish a research network of long-term agricultural field experiments among Asian countries.