It's not hard to understand. For example, traders are worried about the future increase in soybean prices and buy soybean futures contracts to hedge. If soybeans really rise in the future, the price in the spot market will be higher, the cost will be higher, and the spot market will suffer losses. However, it is profitable to buy soybean futures contracts before, and both can protect the capital. Only by following the principle of opposite trading directions can traders lose money in one market and gain money in the other, thus establishing two markets. If the principle of opposite direction is violated, futures trading cannot be called hedging trading, and the result is that either two markets lose money at the same time. Either the two markets are profitable at the same time, which not only does not avoid the price risk, but increases the price risk.