The Chinese Zodiac system uses specific names to refer to dates by fitting characters, horizontal and vertical, and is composed of ten stems (十干, 天干), such as "甲乙丙丁 ," and twelve branches (十二支, 地支), such as "子丑寅卯." The system has been estimated to date back some 3,000 years based on the discovery that the oracle bone script (甲骨文) contained such characters as "丙子, 癸未, 乙亥, 丁丑." It was much later that the 60-year cycle (甲子) composed of ten stems and twelve branches was composed. The calendar marked with a sexagenary cycle started about 2,000 years ago, with the 13th year of the "Fire Rat" (丙子) in 105 B.C. during the Han Dynasty (漢代) in China.The system by which animals were assigned to the twelve branches, i.e. "子" for rat, "丑" for cow, "寅" for tiger and so on, first appeared in the Critical Essays (Lunheng, 論衡) written by the Chinese philosopher Wang Chong (王充) around the second century during the late Han dynasty. Then, the theoreticians of the Five Progresses (Wuxingjia, 五行家) added the Five Elements of Nature (五行), i.e. metal, wood, water, fire and earth (金木水火土), to the ten stems and twelve branches, along with the method of "Mutual Generation or Elimination" (Xiangsheng Xiang Ke, 相生相剋), thus creating a complex matrix to predict not only a person's future but also universal security. Based on this system, it may be groundless to judge one's destiny; however, whenever a year changes, a person may feel insecure or curious about their future in this world, which is often uncertain and confusing. In times of change, it is only human to hope for a new expectation.

Come the New Year, everyone wanted to know their fortune for the year by figuring out what symbolized the year's guardian animal of the Chinese zodiac system. Korean customs included making interpretations out of the destiny and personality of a child born in that year based on the animal of the zodiac system. By welcoming the new symbolic animal of the year, people created meaning out of the animal’s appearance, personality and traits in order to plan a new year full of hope and dreams.

Of course, exactly what influence the twelve zodiac animals had on people's daily life cannot be known; however, in Korea people sought symbolic meanings from each animal and tried to foresee their future. The fact that they received not only wisdom but also behavioral principles from them can be seen in various local customs, documents, relics and historic sites. Most importantly, the Rat was the first among the twelve animals. There are several legends which shed light on this background, including the following: Once upon a time, the King of Heaven wanted to give an important rank to animals, and announced that the first animal to arrive at the gate of the heaven on Lunar New Year's Day would be given the highest title. Upon hearing this news, all of the animals rejoiced and trained hard with the goal of getting there as fast as they could. Of them, the Cow worked the hardest. The Rat, however, while watching all the other animals in training, realized that it would be impossible to win the race as it was so small and weak. So the Rat stuck by the Cow as it trained the hardest. Then, when Lunar New Year's Day arrived and the race started, the Cow arrived at the gate first, but jumping off the Cow's back, yet the Rat passed through it first by leaping from the Cow's back at the last moment. The Cow was indignant, but it had no choice but to accept the second place. Thanks to its intelligence, the Rat won the first rank among the twelve zodiac animals.