I Ching Basics (Brief)

• Hexagram: six lines; upper trigram (top 3) and lower trigram (bottom 3).
• Line: still lines — yin (broken) / yang (solid) — are drawn with colored strokes whose palette follows the trigrams’ attributes (Heaven/Earth/Thunder/Wind/Water/Fire/Mountain/Lake); moving lines — old yin / old yang — are marked with a trailing cross (×) for old yin and a trailing circle (○) for old yang.
• Upper/Lower Trigrams: every hexagram consists of two trigrams — the top three lines form the upper trigram (also called the outer or “use” trigram), and the bottom three lines form the lower trigram (also called the inner or “body” trigram).
• Being in Position (yin/yang suitability by place): counting from the bottom, the six places are 1st (Initial), 2nd, 3rd, 4th, 5th, and Top. Places 1/3/5 are yang‑places; places 2/4/Top are yin‑places. A yang line in a yang‑place or a yin line in a yin‑place is “in position” (de‑wei); otherwise it is “not in position”.
• Original/Changed: changing lines flip to form the changed hexagram. Read Original as body, Changed as application.

Interpreting Changes (by number of moving lines)

• One moving line: read the line text of that moving line in the Original hexagram.
• Two moving lines: read the two moving lines’ texts in the Original; the higher line takes precedence.
• Three moving lines: read the Judgements of Original and Changed together (treat Original as “zhen/ti”—the body, and Changed as “hui/yong”—the application/adjustment).
• Four moving lines: read the two unchanging lines’ texts in the Changed hexagram; the lower one takes precedence.
• Five moving lines: read the only unchanging line’s text in the Changed hexagram.
• Six moving lines: read the Judgement of the Changed hexagram; for Qian (乾) and Kun (坤), read “Use of Nine” / “Use of Six”.
• Texts: the app includes bilingual Judgement/Lines/Image with script switching.