Zero Japan products are made of the finest porcelain quality clay. A lot of handwork is involved in the process from molding to glazing the products. The whole process including the firing in the kiln takes several days. The biscuit firing or first firing at a lower temperature is to dry the clay, after which the glaze is applied by hand. The second firing at a very high temperature for around 18 hours is to make the product waterproof and vitrify the glaze.
The Japanese designer Koji Inoue designed the Zero Japan products with the following three concepts in mind: “highly functional”, “great to touch” and “a pleasure to the eye”.
Antique gold teacups cannot be washed in the dishwasher and cannot be used in a microwave. The glaze will become black when it comes into contact with strong soap or acid, such as lemon juice.k