This paper presents the physical configuration of Kasei-Theory. Physics does not begin with particles, fields, space, or time. It is fixed within a regime in which such entities are already readable. Kasei-Theory locates physical reality within the dec phase of a triadic structure consisting of latent, dec, and col phases. This phase does not describe the totality of possibility. It designates a restricted configuration in which differences are stably readable. Within this configuration, what are called physical laws correspond to stabilized constraints of readability rather than universal descriptions of reality. This paper does not propose new physical laws or reinterpret existing theories. It fixes the structural position in which spacetime, quantum measurement, cosmological expansion, and consciousness are rendered readable. The analysis is limited to the dec phase and does not extend to the latent or col phases. It determines the structural domain in which physics is possible as a readable configuration.