Although the purpose of both childcare centers and kindergartens is to nurture the physical and mental development of preschool children, the difference between a childcare center and a kindergarten is that the former shall also introduce the concepts of health, life and moral conduct. The qualifications of a kindergarten teacher are regulated in Article 12 of the Preschool Education Law as promulgated on November 6, 1981. Therefore, only those persons with the statutorily stipulated qualifications can assume the position of a childcare worker in the public childcare center; and should s/he transfer to a public school kindergarten, his or her previous years of service can accordingly be recognized. Explanatory Letter (79) Jen-Tze No. 22064, issued by the Ministry of Education on May 15, 1990, states: “A person who has previously served as a childcare worker at all levels of a government-owned childcare center and has qualified as a kindergarten teacher, when transferring to a public school kindergarten to be a teacher, may advance one salary level after the fulfillment of every full year of service, and shall be limited in accordance with the maximum level for that position.” The abovementioned Letter conforms to the foregoing Interpretation and hence is not in contravention of the Constitution.