象索引
每個三爻卦（八個之一）會在 16 個六爻卦中出現——8 個以它為 上卦，8 個以它為 下卦。 把同一個 象 在不同位置、不同搭配中橫向看一遍，就會發現它一貫的教學是什麼。 這是 通透 的關鍵：不是讀單卦，是看 系統。
Each of the eight trigrams appears in exactly 16 hexagrams (8 as upper, 8 as lower). Reading the same image across positions and combinations reveals its consistent teaching. This is the heart of systematic reading: not single hexagrams, but the system.
天的圖象。出現在上代表 主導 / 君位 / 父；在下代表 內在剛健、潛力。讀到 乾 立刻想：純粹的推動力在哪裡？
Image of Heaven. Above = leadership, ruler, father. Below = internal strength, latent power. When you see 乾, ask: where is the pure driving force?
地的圖象。出現在上代表 容受 / 群眾 / 母；在下代表 厚實基礎、土壤。讀到 坤 立刻想：誰在承載？
Image of Earth. Above = receptivity, the masses, mother. Below = thick foundation, ground. When you see 坤, ask: who or what is bearing?
雷的圖象，也是龍出沒之處。在上代表 震動、消息傳來；在下代表 啟動、根部的動。讀到 震 立刻想：什麼在 開始 動？
Thunder. Also where the dragon stirs. Above = arousal arriving, news. Below = initiation, motion at the root. When you see 震, ask: what is starting to move?
水 / 險。在上代表 危險從外來、雲雨；在下代表 內裡的險、流動的暗潮。坎是 易經 中最常代表「困難」的卦。
Water and danger. Above = peril from outside, cloud and rain. Below = inner risk, hidden current. 坎 most often signals 'difficulty' in the Yijing.
山的圖象，也是停止的象。在上代表 邊界、阻擋；在下代表 穩定、不動的根基。讀到 艮 立刻想：哪裡是 該停 的位置？
Image of Mountain, also of stopping. Above = boundary, obstruction. Below = stable, immovable foundation. When you see 艮, ask: where is the right place to stop?
風的圖象，也是進入的象。在上代表 緩慢覆蓋、教化；在下代表 順從、滲透。讀到 巽 立刻想：什麼在 細微地進入？
Image of Wind, also of penetration. Above = slow covering, civilizing influence. Below = compliance, seeping in. When you see 巽, ask: what is subtly entering?
火 / 光明 / 依附。在上代表 光照、明示；在下代表 內在的光、依附中的力量。離 永遠帶著「被看見」的特質。
Fire, brightness, clinging. Above = illumination, what is shown. Below = inner light, strength-through-attachment. 離 always carries 'being seen.'
澤 / 喜悅 / 開口。在上代表 表達、流出；在下代表 內藏的喜、底層的水汽。兌 多和 溝通、口、表達 有關。
Lake, joy, opening. Above = expression, outflow. Below = hidden joy, underlying moisture. 兌 often signals communication, the mouth, expression.
更多跨卦索引陸續推出：位索引（哪一爻在 64 卦裡常見什麼？）· 主題索引（領導 / 等待 / 衝突 / 完成）· 64 卦關係圖（錯綜互的可視化網絡）。
More cross-cutting indices coming: the position index (what each line tends to mean across the 64), the theme index (leadership / waiting / conflict / completion), and the 64-hexagram relationship graph.