An Old Example from Plum Blossom Numerology

“Because the character contains the sayings of Plum Blossom and Liuren, a strange wind happened to rise from the southwest and blew straight into the house, so I cast a divination from my sleeve. The southwest belongs to Xun, and wind also generates Xun; adding the You hour yields the number ten, giving Xun changing to Jian (Wind over Mountain). I thought to myself: Xun is under the bed, the wind is fierce — the matter will resolve in an instant! The body agrees with the use; the nuclear trigrams show Water and Fire, with generation but no restraint; it changes to the body overcoming Dui Metal — with Water overcoming, it can instead generate. Both the wording and the divination are auspicious: not bandits, but a marriage alliance!” —— Wild Old Man's Plain Words (Yesou Puyan)

Sanfu's note: He assigns the southwest to Xun based on the Earlier-Heaven trigrams, then adds wind to Xun, hence obtaining the Xun hexagram. Later, with the You hour yielding the number ten, it changes to Wind over Mountain (Jian). Yet he takes Jian's upper Li and lower Kan as “nuclear trigrams showing Water and Fire,” and the transformation into “the body overcoming Dui Metal” is derived from Xun — obtaining the Li and Dui trigrams, i.e., Fire overcomes Metal.

Here, matching by Earlier-Heaven hexagrams and taking the obtained change as the base, with the inner extraction as the use, then taking the position of change and extracting again — taking Li as the body — is yet another school of method.