Elector Frederick William and Count Georg Friedrich of Waldeck, August–September 1655

TASK: take a partial decipherment further: Elector Frederick William and Count Georg Friedrich of Waldeck, August–September 1655
This page: https://dbourdeau.github.io/cyphersolver/further/friedrichwilhelm1655.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/friedrichwilhelm1655.html (read it first: how the text was read, the key, the reading)
  Date:       1655
  Outcome:    key from adjacent plaintext · partial
  Read now:   92.6% of the deciphered cipher tokens give sense (pieces below may be untouched)
  Files:      https://github.com/dbourdeau/cyphersolver/tree/main/targets/friedrichwilhelm1655 (NOTES.md, key, transcription, reading, scripts)

OPEN GAPS (from NOTES.md, "## Remaining gaps")
  1. [needs-physical-access: needs a new source] Line ends of scans 794 and 798 - blocker: needs-physical-access; letters lost in the binding of the left-hand pages (21 context fills in c793, 6 in ps797; 798.06-798.08 have three holes, so the last two sentences of ps797 are thin). Only a new photograph of the opened volume could give them.
  2. [needs-physical-access: needs a new source] 788.20-788.24 and the line ends of scan 788 - blocker: needs-physical-access; four holes, letters lost in the binding.
  3. [illegible: needs a new source] The clear word before "etwa" on 797.20 - blocker: illegible; not read from the viewer image.
  4. [illegible: needs a new source] 787.a "S{i/c}hweden" - blocker: illegible; 2 or 12 not settled on the image.
  5. [open-codes: doable now] Number 51 (813.a, 814.12) - blocker: open-codes; not a letter, from context a person, perhaps the Elector (a guess).
  6. [no-key-material: needs a new source] Scans 723-724 (17 Aug 1655, another code) - blocker: no-key-material; numbers up to four digits mixed with letters, no key of that code is known; the catalogue item stays open for it.
  7. [too-short: needs a new source] "Nebro" (793.11), the meeting place on the Vistula - blocker: too-short; one name with no context to identify it, read from the signs.
  8. [too-short: needs a new source] "Magnus" (814.01) - blocker: too-short; one name in Waldeck's letter, not identified.
  9. [illegible: needs a new source] Erdmannsdörffer 1869 - blocker: illegible; the only online copies are Fraktur OCR with long-s errors (see Prior art); a quotation of these letters cannot be excluded or found from them.

ALREADY TRIED (from NOTES.md, "## Escalation")
  [x] siblings: all 856 scans of the volume are listed in the catalogue sweep; the cipher scans it names (715-819) were opened; Waldeck's own cipher passages are read here (w787, w813). Scans 723-724 are another code, not treated.
  [x] clear-pages: the margin note on scan 819 and the two glosses on scan 797 were found to be decipherments of the time and are used as the held-out check; Waldeck's register copies carry marginal summaries of the clear text only.
  [x] print: Urkunden und Actenstücke VII opened (catalogue vetting); Erdmannsdörffer 1869 searched at integration in two online Fraktur OCR copies (see Prior art): no hit, but the OCR is too poor to exclude a quotation.
  [x] key-rebuild: the key is complete for letters (22 values and 18 = x); 51, a probable code word occurring twice, has no value and no context settles it.
  [x] retry: all documents decrypted with the final `key.tsv`; the remaining holes are binding losses and [51].

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/friedrichwilhelm1655/NOTES.md in full, and the
   key, transcription and reading files it names; lang/README.md (shared language models).
   Work in targets/friedrichwilhelm1655/. 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/friedrichwilhelm1655/. 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+friedrichwilhelm1655&page=friedrichwilhelm1655.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.