Otto von der Malsburg’s cipher letters to Landgrave Wilhelm V, 1637

TASK: take a partial decipherment further: Otto von der Malsburg’s cipher letters to Landgrave Wilhelm V, 1637
This page: https://dbourdeau.github.io/cyphersolver/further/malsburg1637.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/malsburg1637.html (read it first: how the text was read, the key, the reading)
  Date:       1637
  Outcome:    ciphertext-only break · partial
  Read now:   53.0% of the deciphered cipher tokens give sense (pieces below may be untouched)
  Files:      https://github.com/dbourdeau/cyphersolver/tree/main/targets/malsburg1637 (NOTES.md, key, transcription, reading, scripts)

OPEN GAPS (from NOTES.md, "## Remaining gaps")
  1. [no-key-material: needs a new source] HCPortal 504 (f. 18) and 505 (ff. 23-24): decoded, not read after the 23 Oct 2026 re-read on the scans (explicit holes 0.562, 0.545; HCP504/505_reading.md) - blocker: no-key-material; the sentences build, but open codes (504: 212, 122, 120, 123, 148, 260; 505: thirteen) and signs stand in most of them. HCPortal 497 and 506 closed 23 Oct 2026: read (0.632, 0.625)
  2. [no-key-material: needs a new source] ff. 14, 15-16 decoded, not read after the 22 Oct 2026 re-read (clean share 0.167, 0.375; readings HCP502/503_reading.md) - blocker: no-key-material; the sentences build, but two to six open codes or signs stand in most of them; f. 14 also torn at the right edge. ff. 28-29 (HCPortal 507) closed 23 Oct 2026 (r2k): read, 0.662 explicit holes
  3. [no-key-material: needs a new source] ff. 32-33 (HCPortal 509), German news extracts: codes and signs 248, 129, 155, 148, 133, 126, 115, 123, 156, OO, AA, XX, square, GG, CC, KK, LL, V - blocker: no-key-material; clear text transcribed 23 Oct 2026 (r2k), extracts 0.50 explicit holes (record 0.667 with the French letter, kept decoded, not read); the codes and signs stand in nearly every cipher-bearing sentence, occur once or twice and are not in key.txt
  4. [illegible: needs a new source] ff. 32-33 (HCPortal 509): about 30 words of the fast second hand in the extracts - blocker: illegible; unread or doubtful at 2-3x on the HCPortal scans 0032-0033
  5. [no-key-material: needs a new source] about 40 three-digit codes and name signs (193 tokens: 120, 122, 129, 140, 148, 176, 193, 212 ... V, K, f, 4#, +, AA, GG ...) - blocker: no-key-material; mostly single occurrences, five valued from context (128, 130, 188, 253, 273, grade I)
  6. [no-key-material: needs a new source] alphabetic 43, 45 and LL (three labels, five tokens) - blocker: no-key-material; no primary key equation or named parallel, and no demonstrated shared nomenclature with the numerical system; LHA Koblenz 47/4400 remains uninspected
  7. [illegible: needs a new source] alphabetic source alternatives in lines 3, 6, 7, 8, 9 and 10, plus the blot - blocker: illegible; selected 510-position branch and bounded alternatives retained; a human comparison with the original or better authentic imaging is needed to decide ambiguous strokes and the blot's extent
  8. [no-key-material: needs a new source] alphabetic residual forms tqouppen, itzigdn and er ... wurden - blocker: no-key-material; the alphabetic mechanism is recovered, but no independent primary parallel or fair copy has been located to establish the intended forms; literal output and conjectures remain separate, and physical access has not been shown necessary
  9. [illegible: needs a new source] exact reading of the annotation - blocker: illegible; [E?]: Sixt: / cla: remains tentative; a clearer authentic image or comparison with the same hand is needed before expanding it
  10. [no-key-material: needs a new source] provenance of the appended intelligence - blocker: no-key-material; no contemporary source attribution or matching named parallel established; a possible Hoff comparison and original correspondence remain uninspected, without a claim that they require physical access

ALREADY TRIED (from NOTES.md, "## Escalation")
  [x] siblings: all ten records of HStAM 4 h 1411 transcribed; ff. 30-31 duplicate ff. 28-29 and served as a check copy
  [x] clear-pages: no decipherment on any leaf; the address sides (ff. 4, 13, 17) carry no cipher
  [x] known-keys: all 176 HCPortal key records of the Marburg key volumes harvested; keys 5, 30, 38, 49 tried on the digits and 2, 105 on the letter block; none fits
  [x] print: web and LAGIS search for an edition of the letters; none found
  [x] key-rebuild: digit table annealed from the ciphertext and polished over all pages; signs and five codes valued from context
  [x] retry: 236 unread groups re-checked against the scans (24 misreads, 2 doubled groups corrected, 210 confirmed)
  [x] retry: (23 Oct 2026, r2k): 507 reviewed as a reader on decode, duplicate and scan, read (0.662); 509 German extracts transcribed on the scans, still decoded, not read (extracts 0.50)
  [x] retry: (23 Oct 2026, r2b): 497, 504, 505, 506 re-read sentence by sentence on the HCPortal scans; 497 and 506 now read; the b08 spelling normalisation undone in the sibling readings
  [x] retry: (22 Oct 2026, b08): the five unread records re-read sentence by sentence on the HCPortal scans; ff. 28-29 against the duplicate ff. 30-31 (9 readings taken from it); f. 32 one label corrected and the French letter transcribed; f. 3 now reads
  [x] siblings: 18 related leaf transcriptions compared, including the February letter, March duplicate and second LL-like occurrence; ordinary numerical 43/45 are letter values and cannot be transferred as name codes
  [x] clear-pages: address image 0013 and appended-intelligence context considered; no matching deciphered copy of the alphabetic paragraph established, and the annotation does not by itself assign authorship
  [x] known-keys: Sixtinus-family sheets 0040-0042, 0121-0122 and 0123-0126 compared; no matching nomenclature established; the newly located Koblenz 47/4400 catalogue entry has no inspected sheets
  [x] print: the contributor's prior Grotius/Anhalt searches and the Geyso/Hofmann and Oxenstierna comparisons produced contextual parallels and specific missing documents, but no named version of this paragraph
  [x] key-rebuild: the five shifts reproduce the inherited and selected literals; separate source and editorial layers prevent fitting the ciphertext to a candidate identity
  [x] retry: source alternatives combined in the bounded 64-branch audit; local residuals tested against phase changes and a global replacement key, without accepting conjectural plaintext as a source reading

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/malsburg1637/NOTES.md in full, and the
   key, transcription and reading files it names; lang/README.md (shared language models).
   Work in targets/malsburg1637/. 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/malsburg1637/. 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+malsburg1637&page=malsburg1637.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.