There was only a very brief sentence written on the IOU: "On X year, Xmonth, Xday, Lu Dongfeng seeked a medical consultation with Liu Buyan, an earth-level Spirit Medicine Master and took a top saint grade Fire Rejuvenation Pill, worth ten thousand low-grade jade quartz. Here is the IOU as a record and he is to pay Liu Buyan ten thousand low-grade jade quartz within seven days, and if the time limit is exceeded, the interest will be 100 low-grade jade quartz per day."
It can be said that the content on this IOU was not at all different from the facts.
Although there was a clause that interest must be paid beyond the time limit, it was still within reasonable grounds. Such a requirement will appear on any IOU, lest the person who wrote the IOU would delay the payment with excuses.
This IOU was too normal!
However, how could Liu Buyan not play tricks?