The animal cycle can be combined with the Yin-Yang binary cycle, each animal being always associated with a year of the same type; the Dragon, for example, is always yang, and the Goat always yin. In the Gregorian calendar, even years are yang and odd years are yin (strictly speaking, the yin-yang change takes place at the Chinese New Year).
Combined with the cycle of the five elements (metal (jin), wood (mù), water (shuǐ), fire (huǒ), and earth (tǔ)), the whole gives a cycle of sixty different years. Thus we will have the year of the “Metal Rat”, the year of the “Water Ox”, the year of the “Wooden Tiger”. In Japan, the sixty years anniversary is celebrated by a ceremony called kanreki (completion of the calendar). It is interesting to note that combined year-element designations are not used in China. For example, although some Western sites refer to 2018 as the “Year of the Earth Dog,” in China, 2018 is simply called the “Year of the Dog.”
Tradition associates each of the elements with a color: Wood is green, fire is red, earth is yellow or ochre, metal is white and water is black or blue. These colors sometimes appear in place of the elements on Chinese calendars abroad: the year of the Green Rooster or the Red Tiger, for example.
In ancient matrimonial arrangements, couples were matched according to the compatibility of their signs. For example, it was accepted that two Dogs did not go together, but that a Dog and a Pig was a good union; the union of a Water Dog with a Wood Pig will be beneficial, unlike that with a “Fire Pig”, because Water is beneficial to Wood (it engenders it), but controls Fire (it extinguishes it), according to the principles of their interaction according to the theory of the five elements.
Unlike the Chinese signs, each element occupies in turn two consecutive years in a cycle that lasts sixty years. The first year, the element is Yang; the following year the same element is Yin.