Ru ware is the rarest and most revered of all Chinese ceramics — fired for barely two decades around 1100 for the Northern Song imperial court, with fewer than a hundred whole pieces surviving today. Its glaze is the colour the Song called "sky after rain" (雨过天青): a muted duck-egg blue-green, neither blue nor green, laid over a buff biscuit body that warms through at thin edges.

This system treats the glaze itself as the ground. There is no decoration — Ru was prized precisely for what it refused: no painting, no gilding, no dragons. What remains is the fine "crab-claw" crackle webbing the surface, vast quiet negative space, and a single vessel held in focus. It is restraint as the entire aesthetic argument.