The so-called changing hands refers to opening and closing positions in the same direction without increasing positions. For example, many people open 10 lots, and some people close their positions at the same price 10 lots, which is called changing hands. Bilateral opening means that both long and short sides increase their trading positions without closing them, which increases their positions. For example, many parties open positions 10 hands, and the empty side also opens positions 10 hands.