A character who is composed and emotionally flat on the surface, with feeling present but rarely expressed. The term reduces to 4 — the structure.
4Four — foundation. That is the reduction of this term, and the shelf it is read from.
Kuudere combines the English word cool as borrowed into Japanese with the same affection suffix as tsundere. The character is calm, controlled and undemonstrative rather than hostile.
A tsundere is actively abrasive; a kuudere is simply unreactive. The distinction is between someone pushing you away and someone who does not visibly respond either way.
It is also distinct from a dandere, who is quiet through shyness rather than composure. A kuudere is not nervous — they are self-possessed.
The appeal is inference. Because the character expresses little, small deviations carry enormous weight: a slight change in tone, an action taken without comment. The reader is put in the position of reading someone closely, which is more engaging than being told.
This suits manga particularly well, since faces can register minute changes that dialogue would have to state.
Emotional restraint written without interior life produces a character who is merely blank. The type only works when the reader has reason to believe something is being withheld.
The arithmetic is unremarkable and worth doing anyway: 31 across 1 word, reducing to 4.
Four is builder & organizer — structure, labour, and the building of lasting systems. The reference files it as a structure. Read that way, what the entry is really recording is the 4's insistence that what lasts must be built patiently.
Heart's Desire 7, Personality 6: inquiry underneath, responsibility on the surface. The gap between them is where the subject is most interesting.
The 4 confuses the frame for the work. Structures outlive their usefulness, and several entries here describe conventions kept long past their reason. What the 4 still asks is that you look for the constraint the subject was working inside. The other entries that reduce to 4 are collected on The Structure.