After molding, decoration of the work is mostly done by engraving with a carving knife. Inlay, intaglio, embossing, and printing methods are used to depict flowers, trees, birds, animals, clouds, and much more.
When the moisture is wiped and it is starting to dry up, carve the surface lightly with a knife. The carving should be very delicate in order to have a sharp pattern. Thus it needs training. The carved slit is filled with red or white soil with a brush, and waited until drying. Then if they are carved out again using a knife, the different color of the soils reveals the pattern. Then the celadon is glazed with transparent enamel. This is the very method the Samgang Celadon of Koryeo was made.
When the celadon is slightly dried, a sharp knife is used to totally perforate the celadon. The Koryeo Double Bored Celadon where the celadon is formed twice and the outer side is bored is the most famous. In the Three Kingdoms Period, this method was used to vivify the balance and beauty of Celadons.
Intaglio uses sharp carving knife or bamboo knife on dried celadon surface in order to slightly dent the surface. When transparent enamel is coated over it, the pattern is elegantly revealed. There are many great works that uses the intaglio method. Also, if the intaglio is done after applying additional soil or with various tools such as bamboo knife, wooden knife, or sharp metallic knife, one could invent some unique effects.
Embossing is making the pattern stand out. It carves the surface surrounding the pattern, making it the opposite of intaglio. Additional clay could be added to make even more dramatic effect, and it is called 'Bujo.' Bujo has a more three dimensional feeling. Mostly clays are added and then carved into the wanted shape. When embossing, the celadon should be thick to start with so that there are room for scraping. A thin celadon is hard to emboss. Since the patterns stand-out, embossed celadon are used as decorative works rather than daily utensils.
The pattern is made as a stamp made out of wood or clay, and it is pressed towards the surface. It can produce the same pattern over and over again. If a color soil is filled at surface that are printed, it becomes printed inlay celadon.