If it is listed at the same time, there are four contracts, the current month, the next month and the next two quarters. You can see in Wanhua Lane that it is now 1306, 1307, 1309, 13 12.

If weighted: Because futures have a delivery month, the contract will be suspended after each delivery, and replaced by the next year's contract, such as the 1305 contract just delivered on May 17, and now it has become 1405, and the daily K-line is broken, so if weighted, it is a continuous contract to make the K-line trend look more complete.

IF month: June, IF month is IF 1306, and so on.

Main force of IF: the contract with the largest position is now IF 1306, with a position of 95,847 lots.