Voadam
Legend
Maybe so in the Chinese elemental system, I am not that familiar with it.
But while 1e Oriental Adventures had a little bit of fantasy China, (Kung Fu as one of the real world martial arts styles, two of the nations in the two page section on Kara tur countries being historical Chinese fantasy analogues, a few other bits) it was mostly fantasy Japan with Katanas, Samurai, Ninjas, Yakuza, Karate, Jujitsu, two Fantasy Japan countries, races, monsters, samurai honor and clans as the default culture system, wealth and taxes being in the form of rice, the nonweapon proficiencies including things like tea ceremony, Ki instead of Qi or Chi, etc. The consultants were all Japanese players as well and the Introduction mentions the Japanese focus.
I am not familiar with Japanese elemental theory or the inspirations for the Wu Jen class either though so I also can not say whether it is a decent D&D adaptation or not of that and any particular elemental theory. I would guess it is more likely to be Japanese based than Chinese though or maybe even Chinese through a Japanese lens and there may be differences between Chinese and Japanese on specifics for elemental divisions and relationships similar to how I have read Chinese and Japanese dragons are similar but have different specifics like the number of claws or specific animal features and the symbolic meanings of those differences in their specific mythologies and folklore.
