Advancing and retreating tidal water

Shen Cong Sheng presents a lump of water held in a ball that constantly forms waves, not only on the surface but within the water itself. The waves rise and fall together, advancing at one moment and retreating at the next in orderly advance and retreat. Fang Yuan names it advancing and retreating tidal water; it is one of the three great waters of the world and a rank nine immortal material. That rank alone makes it far more valuable than a treasure blue beaver stomach pouch and a falling star rod tree combined, and it has many wonderful uses. ^{ch. 1909}

Shen Cong Sheng offers all twelve portions of advancing and retreating tidal water he has on hand in the exchange for Shen Shang. ^{ch. 1909}