Double opening: a transaction between a new long position and a new short position. That is, both buyers and sellers are new positions (the increased positions are cash) (new positions-new positions). Red double opening is the active opening of long positions to trade the open positions of pending orders; Green double opening is the active opening of short positions.
Double flat: A transaction between an old long selling position and an old short buying position. That is, both buyers and sellers close their positions (Masukura is a negative number of the current quantity) (old-old-empty). Red double flat is the active liquidation of short positions, which is conducive to price increases; Green double flat is the active liquidation of long positions, which is conducive to price decline.
For example, suppose A wants to buy 10 soybean contract, and B wants to sell 10 soybean contract, then the two just happen to clinch a deal. When two positions are opened at the same time, and the variety and quantity of trading contracts are the same, it is called double opening. Double opening means that two positions are opened at the same time, so add positions.
If A wants to buy 12 lots of soybeans, but B still sells 10 lots. Then Party A and Party B can only trade 10 lots, but Party A still needs to buy the remaining 2 lots. At this time, someone needs to sell 2 lots. So let's assume that C just sold 2 positions at this time. Note that these two lots are used to close positions, so the three parties just made a deal. Of course, the three-way transaction is completed at the same time. In this way, of the 12 soybean contracts held by Party A, 10 was sold to Party B for opening positions, and the other two were sold to Party C for closing positions. The trading behavior of Party A, Party B and Party C is called long position opening.