After the 2nd firing, Celadon can be painted and glazed again; this is called surpassing firing. But the surpassed ornaments peel off after prolongeduse, so our Celadon Kiln does not use this method.
Practically for one piece of Celadon to be produced, there are minimum of 24 stages during 70 days. And not all pieces are in perfect shape after the process.
Some Koryeo Celadon did not have 100% successful yield, and what is now called a national treasure mostly have some defects from birth. It can be seen that Celadon are incredibly difficult to make and potters had to undergo vigorous training in order to follow several hundred years of traditionsso that they could produce this beautiful art.