The som (Kyrgyz: сом, sometimes transliterated as "sum" or "soum") is sub-divided into 100 tyiyn (Kyrgyz: тыйын). The som was introduced in May 10, 1993, replacing the Soviet ruble at a rate of 1 som = 200 rubles. In the Soviet Union, speakers of Kazakh, Kyrgyz and Uzbek called the ruble the som, and this name appeared written on the back of banknotes, among the texts for the value of the bill in all 15 official languages of the Union. The word som means "pure" in Kazakh, Kyrgyz, Uyghur and Uzbek, as well as in many other Turkic languages. The word implies "pure gold".