This character represents the jamo ㅸ in isolation. To represent syllable-initial ㅸ, use the choseong form ᄫ. To represent syllable-final ㅸ, use the jongseong form ᇦ.
The use of this, together with several other archaic letters such as ㅿ, was prescribed in the official South Korean guidelines for hangulization of foreign terms (들온말 적는 법, deuronmal jeongneun beop), that were in effect from 1948 to 1958, authored by linguist Choe Hyeon-bae. This system was not consistent with previous and subsequent hangulization systems, and did not see widespread uptake. [1]
This character was also revived to represent the same sound in the International Korean Phonetic Alphabet, an extended hangul alphabet developed by phonologist Lee Hyun Bok in a series of papers beginning in 1971. [2]
This and similar archaic letters are occasionally used in online writing to represent foreign sounds, without closely following either of the above systems.
