The thirty-seventh hexagram, Jia Ren ("The Family" or Clan), places Xun (Wind) above Li (Fire). Wind rising from fire, as warmth generates the moving air, gives the image of influence spreading from within outward, as from the hearth of a well-ordered household. It follows Darkening of the Light in the King Wen sequence.
In the xiantian, or Earlier Heaven, arrangement, the binary order devised by Shao Yong in the eleventh century and traditionally ascribed to Fu Xi, Jia Ren stands 21st of 64, apart from its thirty-seventh position in the King Wen sequence traced above; it was this arrangement the Jesuit Joachim Bouvet sent from Beijing in 1701 to Gottfried Wilhelm Leibniz, who read its broken and unbroken lines as his own binary 0 and 1.
Read from the bottom, the six lines of The Family run yang, yin, yang, yin, yang, yang. A later interpretive layer absent from the original Zhou Yi, the nuclear hexagram (hu gua), treats lines two through four as a lower trigram and lines three through five as an upper one; here they combine as Li over Kan, forming hexagram 64, Before Completion (Wei Ji), a hidden figure first associated with the Han-dynasty scholar Jing Fang, whose Yijing commentary of the first century BCE is credited with the earliest appearance of nuclear trigrams. The Family's King Wen partner is hexagram 38, Opposition (Kui); most of the sixty-four pair this way, related by turning the whole figure upside down, while the eight hexagrams built from a single doubled trigram pair instead by inverting every line. Mawangdui (1973) orders hexagrams by trigram, not King Wen; names here follow Wilhelm and Baynes, 1950, not Legge, 1882.