Unique Ability
Han China's Unique Civic Tree unlocks up to three Traditions — Guanxi, Jin Qing, and Tianxia — each of which stays available as a social policy slot option in any later Age, regardless of which civilization you're currently playing.
Han China runs its own miniature "Great People" system through a unique civilian unit, backed by a Unique Civic Tree that keeps paying dividends long after you leave the Antiquity Age.
Han China's Unique Civic Tree unlocks up to three Traditions — Guanxi, Jin Qing, and Tianxia — each of which stays available as a social policy slot option in any later Age, regardless of which civilization you're currently playing.
The Shì Dàfū is a unique civilian unit functioning like a personal Great People system: each one grants a different reward, can only be received once, and costs more the more of them you've already recruited.
The Great Wall is a Unique Improvement (not a standard building) built along Han China's borders. Like Rome's Forum, Unique Infrastructure of this kind is Ageless — it continues functioning at full effect even after you move into later Ages.