What is Nuclear Hexagram?

A hexagram derived from the middle four lines of the original hexagram. Lines 2-3-4 form the lower nuclear trigram; lines 3-4-5 form the upper. The nuclear hexagram reveals the hidden internal dynamics at work beneath the surface reading. Used in both literary interpretation and Plum Blossom Numerology.

Source: Zuo Zhuan (左傳); Meihua Yishu (梅花易數)