Carbonising Kiln Moduration happens when there is a minimum oxygen supply to kiln after pumping extra oxygen to raise the temperature to very high point. By doing so, fire searches all possible oxygen by going deep inside the pottery itself. This allows much deeper carbonization of actual pottery by slowly raising the temperature and produce extra hard, beautiful looking Shigaraki piece. Please soak it in water for a couple of hours and air dry it prior to use to prevent cracking. It will acquire deeper and shinier complexity on its appearance as you use it, and it is a part of Shigaraki’s charm.