Bilateral opening refers to the simultaneous opening of long positions and short positions in this transaction, and bilateral closing refers to the simultaneous closing of positions. People who change their fingers in the same direction will close their positions and open them.

Because futures are two-way transactions, you can go long or short, so with these kinds of transactions, stocks can only be sold in one direction, so it's good.

For example, if the current trading volume is 20, then double opening means that both of them are short, one is bullish on opening positions 10 long, and the other is bearish on opening positions 10 short, then they are bilateral opening positions. If they all feel that their judgment is wrong and want to close their positions, another 20-bilateral volume will be generated.

Changing hands is the same as stocks, except that more sellers close their positions.

Very verbose, I hope you can understand.