Group 1 - A-shares saw a total of 67 stocks hitting the daily limit up and 3 stocks hitting the limit down during the first half of the trading day on October 21 [1] - The shield machine concept was active, with Zhongxin Heavy Industry achieving a consecutive limit up, and companies like Shanhe Intelligent and China Chemical Geology also hitting the limit up [1] - The cultivated diamond concept strengthened, with Huanghe Xunfeng and Hengsheng Energy achieving consecutive limit ups, and *ST Yazhen hitting the limit up [1] Group 2 - Daya Energy achieved 7 limit ups in 8 days, Hefei Urban Construction achieved 6 limit ups in 8 days, and *ST Aowei achieved 4 limit ups in 6 days [1] - Other notable stocks include Huajian Group and Shangs Development with 3 limit ups in 5 days, and *ST Huawang with 3 limit ups in 4 days [1] - *ST Yuancheng experienced a continuous decline with 7 consecutive limit downs, while Ningbo Zhongbai and Qunxing Toys also hit the limit down [2]