Zi hua

自化, self-transformation. The birth-year 四化 come from the stem of the year someone was born; 自化 comes from a PALACE's own heavenly stem, run through the same table of four, landing on a star standing in that same palace — the palace transforming its own occupant. The Flying Star (飛星) and 欽天四化 lineages treat it as central and read it largely as leakage, a palace spending its quality outward unnoticed; the 三合 lineage barely uses it. A star can carry a birth transformation and a self-transformation at once.