Atacama Compact Array (ACA) is an array consisted of twelve 7-m antennas and four 12-m antennas, which was introduced in ALMA by the participation of Japan. A Preliminary Design Review for this ACA system was held at NAOJ (at Mitaka) on November 10 and 11, and received a high evaluation from the reviewers including some specialists from overseas. The picture shows Ryusuke Ogasawara, SI team leader (in the middle of the front row) and reviewers from abroad with people involved in the review.