The various lists of Chinese IQ by province out there tend to be unreliable. The average IQ of Taiwan, as calculated from the PISA data, is a mere 102.5 or slightly higher; it is silly to expect that of Fujian Province to be any higher than that (the 2018 PISA results for Beijing-Shanghai-Jiangsu-Zhejiang, higher than Singapore, were obviously gamed, though the 2015 ones don’t seem to have been):
Fujian is widely recognized as one of China’s three highest IQ provinces, having been severely overrepresented among imperial examination degree recipients as early as the Song Dynasty, and China is a fairly large and diverse country, so there is no chance at all China’s average IQ is above 100. Since it is best to place one’s estimates on the firmest of grounds, rather than potentially unrepresentative surveys, I have estimated the average IQ of the Chinese provinces by simply assuming a 1-to-1 relationship with provincial GDP per capita, setting the average IQ of Fujian province at 102.5 (the PISA-estimated average IQ of Taiwan), and setting the average IQ of southerly Guangxi province at 82.3 (the PISA-estimated average IQ of Indonesia). This is the most controversial assumption of my model, but there’s no obvious reason to believe it’s wrong. Recall that Guangxi province is, despite excellent infrastructure, actually poorer than Indonesia by PPP, and that the majority of Indonesian ancestry comes from Neolithic China by way of Malaysia (which has a PISA-estimated average IQ of 89.65). The Filipinos also originated from southern China at around the same time, but Guangxi has surely experienced admixture from Hunan and Guangdong since then, which is why I mark Guangxi’s average IQ as the same as that of Indonesia, rather than that of the Philippines.
The model and its results are posted here: https://cdn.discordapp.com/attachments/402265308770992130/817810732573786122/chinaiq.xlsx
So far as I can see, the results check out. Hong Kong’s PISA-estimated average IQ is five points higher than the modeled average for Guangdong province, hardly a severe urban-rural divide. Gansu, the lowest recorded province, has a modeled average IQ of 77.8, almost as low as the Philippines (PISA-estimated average IQ of 77.5) -but, then again, the province is almost as poor as the Philippines by PPP. Shanghai is at 111, slightly higher than Singapore (PISA-estimated average IQ 108.45). The most questionable results are those for the northern provinces, where incomes have obviously been lowered by an overly inefficient state-led economic model -but it is likely using the 2010 GDP per capita data would have placed the average IQ of the northern provinces too high. I doubt Hebei really is as low as 84 or Heilongjiang as low as 78.5.
Overall, the model estimates Chinese average IQ at 91.67, just above that of Serbia (PISA-estimated average IQ 91.35) and higher than those of Chile, Romania, and Malaysia. This estimate is hardly ridiculous – China today is still poorer by PPP than Thailand (PISA-estimated average IQ 86.92), and while there surely is a gap in efficiency between Chinese and Thai capitalism, I doubt it is severe enough to result in China’s average IQ level being similar to that of Western Europe.