Hi, first time posting in this forum. Registered because I started to play this game and curious about this Han China mod (haven't tried it tho).
As a Chinese, I find the rice field I see in this thread somewhat strange. I am not anywhere expertise in the topic, but just want to give my ideas. The rice field here is more like specific "terraces" (you can google this word, and find similar real-life images. Chinese: 梯田 tī tián). This kind of rice field is built on some area with slope, e.g., a hillside. Found a definition on an online dictionary:
For rice fields in Han dynasty, I tried to find a related journal article on models of rice fields from Han period (I translated the title): Funeral models of paddy fields from tombs of the Han period.pdf. The article is in Chinese though, but there is an English abstract and some images that will help. I think, rice fields on flat grounds are more likely to be "large-sized paddy fields" mentioned in this article (See Figure 1). Water in a rice field should be the same or slightly below the ground level. The rice field in this comment might be closer:
Of course, I don't know if there are any other considerations for choosing the current rice field model. Historically it's not wrong, but technically, I am afraid not.