As Mongolia, you'll have to leverage trade routes for military might, whereas China will provide an opportunity to build a real economic powerhouse. I have successfully defined unique adjacencies and its special effects, but the district remains invisible when I build it ingame.

Kublai Khan's unique ability provides an extra Economic policy slot, as well as a random Eureka and Inspiration when establishing a Trading Post in another civ's city for the first time. I am somewhat new to Civ modding and I was trying to create a unique holy site district for Arabia.

The Thanh unique district offers extra Culture for each adjacent district, as well as producing as much Tourism as your Culture output once Flight is researched. Courts provided notice on 1/6/21 of a national breach of judiciary systems and called upon courts to implement new. The bonus is increased if the tiles belong to you, and beginning your turn on either tile grants extra Movement. In terms of military, Vietnamese leader's unique ability is called 'Drive Out the Aggressors' and it grants extra combat strength for units fighting in Rainforest, Marsh and/or Woods. 'Note that unique districts follow the rules of the district they replace in regard to population. Also if you read the description on the Wiki, it says. It was just way too OP, especially for Germany. Once built, the buildings get extra Science, Production or Culture. I think they changed that in the Summer Update so that Unique Districts still follow Pop requirements.

The new civ's unique ability is Nine Dragon River Delta, which requires all land specialty districts to be built on Rainforest, Marsh or Woods tiles. Vietnam and Kublai Khan DLC has brought Ba Trieu as the leader of Vietnam and Kublai Khan as an alternate way to experience China or Mongolia.

Civ 6 unique districts