Middle dan tian (中丹田)
Zhōng dāntián — tanzhong region
Middle dan tian (中丹田) — the storage centre of qi (vital breath), located at the tanzhong region (CV17), at the mid-sternum between the nipples. In Neidan it is the seat of the second transformation, qi → shen: refined qi rising from the lower centre is gathered here and further refined into spirit. The coordinate corresponds to the project's STERNUM_MID landmark.
Point 2 of 3 in Three Dan Tian (丹田)
Cross-tradition overlaps
No overlapping points are registered for this point.
Sources
Huangting Jing (primary_canonical)
Huangting Jing, Inner Classic verses on the Yellow Court and the Crimson Palace, places inner vitality and spirits in central-body palaces; this supports the middle-centre correspondence, while the CV17 placement remains a later interpretive mapping.
Liu Yiming, Awakening to the Tao (secondary_translation)