I have an idea, just like Lanfang can form China, there should also allow Two Sicilies or Sud-italian form Byzantine Empire.

@Maxeon_09 Hmmm... I'm not taking that decision away from a player but I can set the weight to 0 for an AI Heavenly Kingdom

I think the Heavenly Kingdom should not be able to form China through the journal entry

Classic Paradox...

Good news! Since patch 1.7.4, Paradox allowed (almost) every single warlord state to form China now with an accompanying Journal Entry. Bad news is that Paradox did this by making Han a primary culture for all of the warlord states, so Lanfang or a warlord Mongolia still can't form China after a Qingsplosion...

I'm pretty swarmed with work this week, so I'll see how I can synergize this mod with the new China content from 1.7.4 on a later date

Japan might be better being pushed down to the Many Races Under One Union rule, thematically.

Though, if you wanted them to be able to do things situationally, you could always use some flags like I used for this Sinosphere mod:
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=3108195724

Can you give a decision to collapse china?

The HRE screenshot convinced me to subscribe. Well played sir!