Xīn (心) — Heart / Fire
King of organs — fire phase
Xīn (心) — the heart, paired with the fire phase. The Suwen calls the heart 'the sovereign of the five zang' (Suwen 8): it governs the blood and the vessels, houses the shen (consciousness, mental clarity, integrative awareness), and corresponds to the season of summer, the southern direction, the colour red, the bitter taste, and the emotion of joy. In Lingshu 8 the heart-shen pairing is given as the principal axis around which the other zang-mind pairings (liver-hun, lung-po, spleen-yi, kidney-zhi) are organised. Clinically, heart pathology in TCM presents either as deficiency of the shen (anxious agitation, palpitations, insomnia, scattered speech) or as obstruction of the heart's vessels. The heart is the only zang for which the Neijing forbids direct needling — Suwen prohibits puncture at the proper heart, treating instead via the pericardium meridian.
Point 1 of 5 in Five Phases (Wuxing) at the Five Zang Organs
Cross-tradition overlaps
No overlapping points are registered for this point.
Sources
Huangdi Neijing — Suwen, ch. 8 (Ling lan mi dian lun) (primary_canonical)
“The heart is the sovereign of the five zang and six fu — it is the residence of the shen-spirit; from it brilliance issues.”
Huangdi Neijing — Lingshu, ch. 8 (Ben shen) (primary_canonical)
Lingshu ch. 8 (Ben shen) states the heart–shen relation and sets it within the series of zang-associated mental faculties; the fire pairing and colour are rendered here from the broader Neijing correspondence system.
Maciocia, Foundations of Chinese Medicine (secondary)