1. To look is to look carefully inside and outside the hot ceramic coffee cup. See whether the glaze is smooth and lubricated, whether there are scrapes, holes, black spots and bubbles; Second, to see whether the shape is regular, deformation; Third, see whether the picture is damaged; Fourth, see if the bottom is flat, must be placed flat, no burr.
2. To listen is to hear the sound made when China is knocked on. If the sound is clear and pleasant, it indicates that the porcelain is fine and dense, without cracks. When fired at high temperature, porcelainization is complete. If the voice is hoarse, it can be determined that the porcelain is cracked, or the porcelain is not complete. This kind of porcelain cracks easily when hot and cold.
