This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

One of the more notable applications of printing technology was the chao, the paper money of the Yuan. Chao were made from the bark of mulberry trees. The Yuan government used woodblocks to print paper money, but switched to bronze plates in 1275. The Mongols experimented with establishing the Chinese-style paper monetary system in Mongol-controlled territories outside of China. The Yuan minister Bolad was sent to Iran, where he explained Yuan paper money to the Il-khanate court of Gaykhatu. The Il-khanate government issued paper money in 1294, but public distrust of the exotic new currency doomed the experiment.
What was the Yuan's paper money called?

While on one hand the Heian period was an unusually long period of peace, it can also be argued that the period weakened Japan economically and led to poverty for all but a tiny few of its inhabitants. The control of rice fields provided a key source of income for families such as the Fujiwara and were a fundamental base for their power. The aristocratic beneficiaries of Heian culture, the Ryōmin (良民 "Good People") numbered about five thousand in a land of perhaps five million. One reason the samurai were able to take power was that the ruling nobility proved incompetent at managing Japan and its provinces. By the year 1000 the government no longer knew how to issue currency and money was gradually disappearing. Instead of a fully realised system of money circulation, rice was the primary unit of exchange. The lack of a solid medium of economic exchange is implicitly illustrated in novels of the time. For instance, messengers were rewarded with useful objects, e.g., an old silk kimono, rather than paid a fee.
What crop was a primary source of income during the Heian period?

In 2012, news was released about a new farming site discovered in Munam-ri, Goseong, Gangwon Province, South Korea, which may be the earliest farmland known to date in east Asia. "No remains of an agricultural field from the Neolithic period have been found in any East Asian country before, the institute said, adding that the discovery reveals that the history of agricultural cultivation at least began during the period on the Korean Peninsula". The farm was dated between 3600 and 3000 B.C. Pottery, stone projectile points, and possible houses were also found. "In 2002, researchers discovered prehistoric earthenware, jade earrings, among other items in the area". The research team will perform accelerator mass spectrometry (AMS) dating to retrieve a more precise date for the site.

When was the earliest known Asian farm site found in South Korea?