 Ash glazing began around 1500 BC, in China during the Shang Dynasty, initially by accident as ash from the burnt wood in the kiln landed on pots.Around 1000 BC, the Chinese apparently realized that the ash covering the pieces was causing the glaze so they started adding the ash as a glaze before the pot went into the kiln.Ash glaze was the first glaze used in East Asia, and contained only ash, clay, and water.