ACSMO has been held biannually by the Asian Society for Structural and Multidisciplinary Optimization (ASSMO) taking over the series of symposia called the China-Japan-Korea Joint Symposium on Optimization of Structural and Mechanical Systems (CJK-OSM) to exchange idea, and to discuss research in the field of structural and multidisciplinary optimization. Due to COVID-19 ACSMO 2020 was held online. Although we still cannot predict the end of the pandemic, we sincerely hope to hold ACSMO 2022 face to face in Matsue.