Kasei-Theory IV.Fuka: Fuka Without Absence

This paper fixes Fuka within Kasei-Theory as a non-modal fixation of non-established fixation-form. Fuka is not absence, negation, failure, limitation, contradiction, exteriority, or origin. Fuka does not designate what is missing, what is denied, what fails to appear, what lies outside readable configuration, or what remains beyond access. Fuka is fixed only where fixation-form, formation-form, return-form, application-form, and translation-form are not established within readability. This paper does not explain Fuka as impossibility, incapacity, prohibition, or negative ontology. It does not derive Fuka from boundary, Kagen, unreadability, collapse, Ka, Ka-readout, or Ka-trace. It fixes Fuka as a structural position in which the form of establishment is itself not established. No causality is introduced. No temporality is introduced. No subject is introduced. No relation is introduced. No transition is introduced. No derivation is introduced. No generation is introduced.