In addition to the Japanese name "Cold Day", watercress is commonly known as "Chae Yeon" (a vegetarian bird's nest, you can know how hard watercress is frozen just by listening to this name), and other names include agar, agar (from the name of the material) and Chinese cabbage (called Chinese cabbage in Hong Kong).

Traditionally, the cold weather in Japan is in winter, and many different cold weather can be made (the practice is of course a trade secret), but cauliflower can not be collected only in winter, and it is certainly not only produced in Japan, but also in Portugal, Spain and Argentina.

"Cold weather" is easy to solidify, and it is also quite easy to be used as a jelly solidification medium. Since last year, it has been widely used as a daily diet by slimming people. At present, dry products and ready-to-eat packaging have been developed and recently added to desserts more widely to achieve the purpose of reducing calorie intake.