Primary, resulting and structural hexagrams
All relationships are calculated from the six-line yin/yang sequence, bottom to top. They do not depend on associations with names or generate additional fortune judgments.
Five relationships
The primary hexagram is the original cast. The resulting hexagram changes old yin 6 to yang and old yang 9 to yin; young yin 8 and young yang 7 remain unchanged.
The complementary hexagram reverses each line’s polarity; the inverted hexagram reverses the line order. The nuclear hexagram uses lines 2, 3, 4 of the primary as its lower trigram and 3, 4, 5 as its upper.
How to check
Number all six lines from bottom to top. Record the yin/yang sequence, then reverse polarity, reverse order or extract the inner lines. Use the resulting upper and lower trigrams to look up the hexagram among the 64.
Some hexagrams are unchanged by inversion, or have a nuclear hexagram identical to the primary. These are normal structural results, not missing calculations.
Reading limits
Complementary, inverted and nuclear hexagrams show structure; the resulting hexagram shows changing-line transformations. Structural relationships alone are not certain fortune conclusions. Return to the primary hexagram, changing lines and sourced classical texts.