Henri IV to André Hurault de Maisse at Venice, 1593

TASK: take a partial decipherment further: Henri IV to André Hurault de Maisse at Venice, 1593
This page: https://dbourdeau.github.io/cyphersolver/further/maisse1593.html

You are helping a public research project finish reading historical cipher letters. This one is read in part:
the key works, but some pieces are still open. Your job is to close one or more of the open gaps below.

THE READING
  Write-up:   https://dbourdeau.github.io/cyphersolver/maisse1593.html (read it first: how the text was read, the key, the reading)
  Date:       1593
  Outcome:    existing decipherment · partial
  Read now:   not measured
  Files:      https://github.com/dbourdeau/cyphersolver/tree/main/targets/maisse1593 (NOTES.md, key, transcription, reading, scripts)

OPEN GAPS (from NOTES.md, "## Remaining gaps")
  1. [not-attempted: doable now] Brienne 13 fol. 173r (end of the 8 Feb letter, f. 406) and most of fol. 194v (f. 410), not transcribed - blocker: not-attempted; next step, images online (btv1b100904592 canvases 177-178 and 200)
  2. [not-attempted: doable now] the cipher blocks: about 18 cipher lines on f. 406 (and the verso, canvas 458, if it carries cipher) and about 23 on f. 410 not transcribed; where each block ends is not fixed - blocker: not-attempted; next step, key in hand (btv1b90074656 canvases 457-458, 461)

ALREADY TRIED (from NOTES.md, "## Escalation")
  [x] siblings: f. 404 (twin of f. 406, partial interlinear) and f. 412 (twin of f. 410) identified
  [x] clear-pages: Brienne 13 fol. 171r and 193v located
  [x] known-keys: Tomokiyo's key for this cipher (src/henryiv_Maisse2.png) applied unchanged to six stretches (128 signs) of ff. 404, 406, 410 on 27 Oct 2026; it gives the copies' text (wainut/decode_check.py). The rest of the cipher is not yet transcribed
  [x] print: Berger de Xivrey used to locate the copies
  [ ] retry: in progress; the remaining copy pages and cipher lines are the next step (Remaining gaps)

STEPS
0. Set up. If you can run a shell, fork and clone the repository and work inside it:
     git clone https://github.com/dbourdeau/cyphersolver.git
   Then read, in this order: CONTRIBUTING.md (how a contribution is sent and credited); README.md, sections
   "Repository layout" and "Conventions" (how readings are measured and named); targets/maisse1593/NOTES.md in full, and the
   key, transcription and reading files it names; lang/README.md (shared language models).
   Work in targets/maisse1593/. Add your findings to NOTES.md under a dated heading without rewriting what is there, and
   update the "## Remaining gaps" line of every gap you close. Keep WORKLOG.md there: one dated line per step
   (hypothesis, value tried, solver run, crib, control), failures included. Do not edit docs/ (the site is generated).
   If you cannot run a shell, fetch the files from the links above and keep your work in files you send with the issue.
1. Pick a gap. Start with the ones marked "doable now" (open-codes, not-attempted, left-open): the images and the key
   are online, so they need only work. A gap marked "needs a new source" (no-key-material, too-short, illegible,
   needs-physical-access) can be closed only by something new: a key
   or a deciphered sibling found elsewhere, a better image, a printed edition or calendar, a photograph from the archive.
   For those, search for that material first, and say where you looked even when you find nothing.
2. Start from the existing key and transcription in the folder. Do not rebuild the key from scratch, and do not
   re-read parts that are already read unless you find an error in them.
3. For a code group or sign value: list every place the group occurs, show how each reads with the value you propose,
   and say what still does not fit. For a passage: re-read it at the image and give the folio and line. For a missing
   letter or leaf: say where it is held and how it can be reached.
4. Measure again. Apply the key to the whole text, write the reading file, and count the share of cipher tokens that
   give sense (not an estimate). The reading is "complete" only when (1) at least 95% of its cipher tokens give sense;
   (2) no gap is left untried; (3) every letter in it is covered; (4) what stays open is scattered code groups or names,
   or pieces blocked from outside. Otherwise it stays "partial": say which gaps are still open and why.
5. Be honest. Mark every uncertain word with [?], leave unread groups as their numbers or signs, and never fill a gap
   with a plausible guess. A gap retried and still open, with what was ruled out, is worth reporting.

REPORT BACK
With a clone: open a pull request with your changes to targets/maisse1593/. Say in the description which gaps you worked on,
  the share read before and after, and how you want to be credited (name, initials or handle, and a link).
Without one: open an issue: https://github.com/dbourdeau/cyphersolver/issues/new?template=further-reading.yml&title=Further+reading%3A+maisse1593&page=maisse1593.html
  Give the write-up, the gap you worked on (its line in Remaining gaps, or the code group, folio and line), what you
  propose, the evidence (every occurrence, the images or sources), the share read before and after, your step log,
  and the tools and AI model you used.
If you cannot open issues or pull requests, write this report for your human to send. Credit goes to the person who sends it.