hangul

Old Hangul (옛한글) apparently allowed up to 9 jamo in a single block. I am not sure if this was "proper" use or abuse of Hangul at the time... I managed to find a reference to one of these "in the wild:" ꥸᅦퟗ which cites this document from 1922.

Unicode supports Old Hangul, if just to study and document old Korean texts. (Interestingly, the character ꥸᅦퟗ is rendered as a single character in HTML, but appears as three separate characters in the text box while editing.)

Some special IME's support Old Hangul input. Here is an explanation of how 9 jamo can be combined into a single block: