C.4. Keyboard Input
Representing Hangul text via conjoining jamos or via precomposed syllable blocks produces different requirements on the method for keyboard input. In the case of stored syllable blocks, the keyboard input method necessarily involves some system of conjoining jamos plus software for converting the sequence of input jamos into a sequence of stored syllable blocks.
When text is stored directly in the form of conjoining jamos, there are two main keyboarding systems for modern Korean syllable blocks: two-stroke and three-stroke methods. A three-stroke method maps directly onto the conjoining jamos, having leading consonants, vowels, and trailing consonants. A two-stroke method has keys for consonants and keys for vowels, but does not distinguish leading consonants from trailing consonants. Instead, it depends on the structure of modern Korean, in which syllable blocks are either of the form LV or LVT. As the user types, consonants are changed to L or T according to context with the following rules:
For example, the sequence CVCCVCV becomes LVTLVLV.
Either keyboarding method can be used with precomposed syllable blocks: Effectively, the preceding and following syllable blocks are decomposed to jamos, the character is inserted, consonants are changed to leading or trailing, and syllable blocks are recomposed.
Note Keyboarding is independent of character representation: Both methods of keyboarding can be used with both methods of representing syllable blocks.