本文考論《左傳》所記韓宣子聘魯所見之“易象”，應指禮制中的陰陽之義，非如杜預所指“上下經之象辭”。這種禮制中的陰陽之義，其實普遍存在周代禮制中，溯其源則可上溯殷周之際，殷代尚陰，周代尚陽。今《周禮》、《禮記》諸篇所見“禮”中陰陽之義，即其遺迹。《歸藏》、《坤乾》爲殷商王朝典册，《周易》則昭示周民族尚陽主變的立國精神。自東周以降，王者之迹熄，《易》象的施用，雖仍本於前代，用於政治，但終於因禮教大義衰微，竟流而爲筮人問卦以附會人事的工具。《左傳》記筮例凡十九則，筮人多用“象”解説，《易》象學説一時看似鼎盛，從歷史角度考察則爲衰微。後人用《左傳》筮例，反證《周易》爲占筮之書，並不合宜。

This paper re-examines the term “yi-xiang”（易象, metaphors of the Changes）mentioned by Han Xuanzi in the Zuozhuan （左傳, Zuo's Commentary on the Chunqiu）, arguing that Han was actually referring to the illustration of yin and yang reflected in the national rituals of Zhou dynasty conducted in the Lu. Actually the national rituals of the Zhou dynasty contains two different features: the “yin” part which mainly relates to feminine, plural numbers, nighttime and negative, while the “yang” part which mainly relates to masculine, odd numbers, daytime and positive. We can further trace back to the major difference between the ideologies of the Zhou dynasty which admires “yang” and the Yin dynasty which admires “yin”, justified by the philosophies of the Zhouyi and Guicang/Kunqian. Later on in the Chunqiu period following the decline of the Zhou regime and its ritual system, the political connotation of yin and yang diminished, the Zhouyi was then broadly used as a text for divination and fortune telling.