The 16th Prince of this drama is based on Emperor Xiaozong of Mid-Ming Dynasty, widely known as Hongzhi Emperor. Current timeline of Ep 20 is 16th Prince/Current Emperor's 5th year of reign in the drama & here comes the topic of salt reform in the court for which Zhao Ling is put in Charge of. This proposed "Silver-for-salt" method historically represents "Hongzhi Salt reform" 1492, 5th year of Hongzhi Emperor's reign.

Traditional salt trade practice (before reform):

Since the establishment of Ming Dynasty, in order to solve the problem of supplying military provisions to the troops stationed on the remote northwestern border, "Kaizhong system" was implemented (Kaizhong fa, 開中法/ "Salt-for-Grain"). In this system, Merchants would transport grain or Military supplies to the northern border army at their own expense. The government would issue a corresponding number of "salt permits" based on the amount of grain transported. Merchants would then use these salt permits/ "Salt certificate" (盐引 / yán yǐn) to collect government-issued salt from the salt fields in the coastal production areas like Huaihe and Zhejiang regions, and then sell it in All designated areas at high Price with great profit. This policy greatly stimulated the enthusiasm of the merchants to supply military rations in the early Ming Dynasty. Merchants in Shanxi and Shaanxi provinces rose rapidly and became extremely wealthy. This "salt certificate system" significantly reduced the burden on the government in transporting military provisions, prioritizing the stability of border troops. (To cut down on transportation costs, merchants hired local farmers to grow grain near the northern borders, building vibrant agricultural colonies!)

But By the late 15th century, this "Salt-for-grain" system started to fail due to rampant corruption. Powerful eunuchs, imperial relatives, corrupted officials obtained massive amounts of salt certificates through favor rather than grain delivery. Real merchants who actually delivered grain to the borders arrived at the salt depots only to find long waiting lists. Some waited decades to claim their salt, ruining them financially. & "salt certificates" became numerous while salt production was limited. Because Salt permits were losing their real-world value, Many merchants stopped delivering military's food supply in the northwest border region, leaving Military garrisons critically undersupplied.

Hongzhi Salt Reform :

The Ming Empire was already riddled with problems & on the verge of collapse. This drama takes place at this crucial turning point. Emperor wanted to eliminate corruption from the court, & replenish the National treasury. The previous Salt-for-grain was an open market method, it never allowed silver to enter the national treasury. In this reform method of "silver-for-salt" (Kaizhong Zhese System /开中折色制), Merchants would directly purchase salt permits with silver, & the silver would go directly into the national treasury. The emperor is the biggest beneficiary of this reform, as the national treasury was replenished, and annual revenue increased by millions of taels of silver. Suppressing the powerful and wealthy was something emperors throughout history had always been happy to do, and this reform had a significant impact on those with landholdings in border towns. In this process, Salt reform & punishing corrupt officials are going hand in hand for the Emperor, because the traditional salt trade is a crucial source of profit for corrupt officials and a chain that maintains their alliance. Only by breaking the existing salt system and scattering corrupt officials can a way out be created for those at the bottom of society.

Damaged party : The border troops, represented by Commander Wang

However, this short-term benefit came at the expense of supplying provisions to the northwestern army and maintaining border stability. Without merchants directly delivering provisions, the government had to rely on transport commissioners to purchase and deliver grain, and delays in supply could be fatal. The army's food supply would be severely hampered, significantly reducing its combat effectivenes. But it's a clever deliberate move by the imperial court to weaken the power of border troops as The Military garrisons now would fully rely on the imperial court for grain transport.

Zhao Ling's dilemma - He is acutely aware that on one hand, the young emperor's urgent need for the national treasury was paramount; on the other hand, he was keenly aware of the "compensation for losses" policy's abandonment and betrayal of the Northwest Army, and that corrupt officials in the court hoped to use him to "cover up the losses"...Although Emperor trusts him & puts him in charge of the whole matter, He has become nothing more than a pawn in the emperor's hands.