Stoicheia is a 405M-parameter character-level masked-diffusion encoder for Ancient Greek (d_model 1024, depth 32, banded attention: three of every four blocks attend within a 256-character window, the fourth globally). Its input is factored into five aligned planes -- letters, word/sentence boundaries, diacritics, capitalization, punctuation -- each of which can be masked independently to an explicit unknown state at inference. That is what lets one model read an edited text, scriptio continua, and a lacuna of unknown length without changing anything but its input.

Anonymous release accompanying a paper under review.

Vowel length alone: long versus short at every ambiguous bare α, ι or υ. Trained on a silver corpus of ~130,000 verse lines built by exact constraint propagation -- a solver accepts a line only when exactly one metrical grammar scans it, and fixes a dichronon only when every accepting parse agrees -- plus converted syllable-weight markup, all checked against the evaluation benchmark to prevent leakage.