Katabasis — the ritual and mythic descent to Hades — runs through every strand of Greek Mystery tradition. Odysseus descends to consult the dead. Orpheus descends to retrieve Eurydice. Persephone descends by force and returns transformed. The Eleusinian initiates ritually reenacted the descent in darkness before seeing the light. Hex 29 (The Abysmal) is water over water: the danger that is not a single crisis but a sustained passage through darkness, where the only way out is through. Hex 36 (Darkening of the Light) is the light driven underground — the sun entering the earth, King Wen imprisoned. Both hexagrams counsel the same thing the katabasis teaches: do not resist the descent. Maintain your inner light. The underworld is not punishment — it is curriculum.