The main lock position is pulled up, which means that the dealer holds a large number of chips and pulls up after being in the high control position. Generally concerned by the market, the stock trend is stronger than the index. Locking-an important magic weapon of master control. The so-called lock-in is an operation method in which futures traders open positions in the same amount but in the opposite direction, so that no matter where the futures price changes (or rises or falls), the position profit and loss will not increase or decrease.