Unsolved Catalogue · no. 207 · class A · priority 5.9 · in progress

Johann Joachim von Rusdorff to Axel Oxenstierna, The Hague, 1628, three letters in cipher (R4333-R4335)

One remaining key-box ciphertext that resisted a first attack, and Oxenstierna correspondence of 1628 and 1633 with a key collection that may hold their keys.

Date
1628
Correspondents
unknown → Camerarius?, Amsterdam; Rusdorff → Oxenstierna; Swedish agent → Oxenstierna
Place
Stockholm
Language
Latin, German, Swedish
Held at
Riksarkivet, Oxenstierna af Södermöre, Ser. B, E 701 (DECODE R4333-R4335)
Images
DECODE R4333 · DECODE R4334 · +5 more records

In progress here. targets/oxenstierna1633 is working on this cipher (status: in progress — surveyed only; the codes and the interlinear decipherments of the time are not transcribed.). targets/riksarkivet4284 is working on this cipher (status: in progress (26 Oct 2026). **Key matched: DECODE R4325, the horizontal alphabet strip on I25940** (Dolly). targets/rusdorff1628 is working on this cipher (status: in progress — surveyed only; nothing transcribed or attacked.). Read its NOTES.md before you start, and hand it to your agent with this page: it records what was transcribed, tried and ruled out, and the next step.

Hand this page to your AI agent

Give your agent (Claude, ChatGPT or any assistant that can open web pages) this address and ask it to do the task on the page:

https://dbourdeau.github.io/cyphersolver/solve/207.html

Or copy the block below into the chat. It is the whole task: what the cipher is, where the images are, what has been tried, the steps, and how to report back.

TASK: help read Unsolved Catalogue no. 207 of the cyphersolver project
This page: https://dbourdeau.github.io/cyphersolver/solve/207.html

You are helping a public research project read historical cipher letters that nobody has read yet.

START HERE: the project is already working on this cipher. Read these notes before anything else and
build on them; they record what was transcribed, tried and ruled out, and the next step:
  https://github.com/dbourdeau/cyphersolver/blob/main/targets/oxenstierna1633/NOTES.md  (status: in progress — surveyed only; the codes and the interlinear decipherments of the time are not transcribed.)
  https://github.com/dbourdeau/cyphersolver/blob/main/targets/riksarkivet4284/NOTES.md  (status: in progress (26 Oct 2026). **Key matched: DECODE R4325, the horizontal alphabet strip on I25940** (Dolly)
  https://github.com/dbourdeau/cyphersolver/blob/main/targets/rusdorff1628/NOTES.md  (status: in progress — surveyed only; nothing transcribed or attacked.)

THE CIPHER
  Title:          Johann Joachim von Rusdorff to Axel Oxenstierna, The Hague, 1628, three letters in cipher (R4333-R4335)
  Date:           1628
  Correspondents: unknown → Camerarius?, Amsterdam; Rusdorff → Oxenstierna; Swedish agent → Oxenstierna
  Place:          Stockholm
  Language:       Latin, German, Swedish (expected)
  Held at:        Riksarkivet, Oxenstierna af Södermöre, Ser. B, E 701 (DECODE R4333-R4335)
  Images/records:
    - DECODE R4333: https://de-crypt.org/decrypt-web/RecordsView/4333
    - DECODE R4334: https://de-crypt.org/decrypt-web/RecordsView/4334
    - +5 more records

WHAT IS KNOWN
  Known so far (checked 21 Oct 2026): Bremen letters of 1631 (R4330-R4331) deciphered in full here, key recovered from the interlinear glosses (riksarkivet1628). R4282 key recovered ciphertext-only by George Lasry (decode4282, PR #33). R4306 deciphered in part by George Lasry with CTTS and Opus 5.5, 17 Oct 2026 (sweden4306, PR #42); four code values open. R4336-R4337 (Rusdorff, London, Feb 1625) key recovered ciphertext-only by George Lasry with CTTS and Claude Opus 5.5, 21 Oct 2026 (rusdorff1625, PR #72); codes 628 and 701 open.
  Still open: All cipher passages; surveyed only (targets/rusdorff1628). The rusdorff1625 key does not fit R4333.
  History and prior art: DECODE R4284–R4341, 8 records in four different ciphers, each its own entry since the one-key split of 14 Oct 2026. Viewed 21 Sept 2026. The two Bremen letters of 1631 (R4330–R4331, riksarkivet1628.html) are read and removed from this entry; R4282 was deciphered by George Lasry (decode4282.html). R4306: contributed partial Dutch decipherment by George Lasry, transcribed with CTTS then solved with Opus 5.5 (17 Oct 2026; sweden4306.html, which also records this project's failed attempt of 21 Sept 2026); pencilled 1632? and Amsterdam attribution remain qualified, four code identities open. R4336–R4337 turned out to be Rusdorff's London letters of February 1625 in a homophonic cipher with an alphabetical nomenclator; key recovered from the ciphertext by George Lasry (21 Oct 2026, PR #72; rusdorff1625.html) and removed from this entry. Open: R4284 (Latin 1628, Camerarius docket; riksarkivet4284.html) — attacked with Latin annealing and against two box keys, not broken; R4333–R4335 (Rusdorff → Oxenstierna 1628, another cipher; rusdorff1628.html) and R4338–R4341 (E 708, Swedish, June 1633, not 1646; glossed in part at the time; oxenstierna1633.html) surveyed only. Narrowed to the unread part and restored 2 Nov 2026.
  Outcome so far: In progress here, in targets/oxenstierna1633/ and targets/riksarkivet4284/ and targets/rusdorff1628/ (earlier: attempted, open).
  Check first: Fetch the images and the key record(s); test the key on the first lines.
  Class A: a sibling letter with a decipherment is in the same volume or series, so matching it is the first move.
  Project notes (read these before anything else; they record what was tried and ruled out): https://github.com/dbourdeau/cyphersolver/blob/main/targets/oxenstierna1633/NOTES.md
  Project notes (read these before anything else; they record what was tried and ruled out): https://github.com/dbourdeau/cyphersolver/blob/main/targets/riksarkivet4284/NOTES.md
  Project notes (read these before anything else; they record what was tried and ruled out): https://github.com/dbourdeau/cyphersolver/blob/main/targets/rusdorff1628/NOTES.md

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/oxenstierna1633/NOTES.md (everything
   already tried on this cipher, with the files it used); and lang/README.md (shared language models).
   Put all your work in targets/oxenstierna1633/: transcription, key, decipherment, scripts. Add your findings to its NOTES.md
   under a dated heading, without rewriting what is there. Keep WORKLOG.md there too:
   one dated line per step (transcription, hypothesis, solver run, crib, key found, control), failures included.
   Do not edit docs/ (the site is generated and rebuilt on merge) and do not commit large images: link them.
   If you cannot run a shell, do the same work in files you keep and send them with the issue below.
1. Make sure it is still unread. Search the web and the literature for the shelfmark, the correspondents and the date:
   printed editions and calendars of the correspondence, Satoshi Tomokiyo's cryptiana pages
   (https://cryptiana.web.fc2.com/), the DECODE record and the files attached to it, and the project notes above.
   If a decipherment already exists, stop and report where it is. That is a useful result.
2. Get the images. For Gallica items, a page image is
   https://gallica.bnf.fr/iiif/ark:/12148/<ark>/f<page>/full/full/0/native.jpg (page numbers from the manifest).
   DECODE records (de-crypt.org) need a free account: if you cannot log in, ask your human to download the images for you.
3. Look for key material before attacking the ciphertext, in this order: a decipherment written between the lines or
   in the margin; a clear copy or a deciphered sibling letter in the same volume or DECODE series; a key sheet from the
   same office and years (DECODE key records, Tomokiyo's articles, printed editions); clear passages in the letter
   itself that can serve as a crib.
4. Transcribe exactly what is on the page: one token per sign or number group, line by line, with folio and line
   numbers, unclear signs marked with ?. Keep the transcription as a file. It is worth sending even if nothing else works.
5. If no key exists, identify the system (count the distinct symbols, tokens and repeats: simple or homophonic
   substitution, nomenclator with code words, syllabary, two-digit figures) and recover the key from the ciphertext
   with a solver scored on a language model of the period (Latin, German, Swedish). In the clone, use the shared models in lang/
   (from lang import lm; lm.load('<model>'), lm.best_language(text)) rather than building your own; add a corpus there
   if none fits. Before trusting a result, run the same solver on a control text you encipher yourself in the same
   system and at the same length. If it cannot solve the control, its output on the real letter means nothing.
6. Measure the result against the project's bar (README.md, Conventions). A text is "complete" only when (1) at least
   95% of its cipher tokens give sense, counted from a reading file, not estimated; (2) no gap is left untried;
   (3) every letter in the item is covered; (4) what stays open is scattered code groups or names, or pieces blocked
   from outside (no key material, too short, illegible, needs the archive). Otherwise it is "partial": say which
   pieces are open and why. Mark every uncertain word with [?] and leave unread groups as their numbers or signs.
   Never fill gaps with plausible guesses. A failed attempt that records what was ruled out is still a contribution.
7. Name how the text was obtained with one of the project's methods (do not write just "solved" or "read"):
     - ciphertext-only break: The key was rebuilt from the ciphertext alone: frequencies, solvers, pattern words, the order of the key. No plaintext and no existing key was used. If someone had solved the same text earlier and it was found only afterwards, the write-up says so: an independent re-solution.
     - key from external plaintext: The key was rebuilt by matching the ciphertext against a plaintext found elsewhere: a printed edition, a calendar of state papers, a copy of the same letter in another archive.
     - key from adjacent plaintext: The key was rebuilt from plaintext next to the ciphertext: a partial decipherment written between the lines or in the margin, clear passages in the same letter, a deciphered copy in the same file.
     - external key matched: An existing key that had not been connected with this document (a key for another correspondent or series, a key sheet filed elsewhere) was found to fit, and applied.
     - known key applied: The key was already identified for this document or its correspondence (on its archive or DECODE record, published for it, filed with it) and was applied. The work is transcription and decipherment, which is not mechanical when the key is polyphonic or variable-length.
     - existing decipherment: A complete decipherment already existed (between the lines, on a separate copy, or in print). The work was transcribing the cipher and checking the decipherment against it.
     - not solved: Attempted; neither the key nor the text was obtained. What was learned is recorded. A target whose key was obtained but whose text does not read keeps the method that obtained the key, with extent "none (text not read)".
     - not applicable: Not a cipher (clear text, shorthand, a key sheet, instructions), or the item could not be reached.

REPORT BACK
With a clone: open a pull request with your targets/oxenstierna1633/ folder. Say in the description how you want to be
  credited (name, initials or handle, and a link) and include the same points as the issue below.
Without one: open an issue: https://github.com/dbourdeau/cyphersolver/issues/new?template=solution.yml&title=Solution%3A+catalogue+207&target=catalogue+207
(other kinds of contribution: https://github.com/dbourdeau/cyphersolver/issues/new/choose). Include:
  - Target: catalogue 207
  - the documents and the images you worked from;
  - the key: sign-to-value table, code groups with values, nulls;
  - the decipherment line by line against the ciphertext, with uncertain passages marked;
  - the method (step 7), the share of tokens that give sense, complete or partial (step 6), and whether the
    reading was already published anywhere;
  - your step log (WORKLOG.md), and the tools and the 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.

Where the cipher is

Cipher located and confirmed. R4284 pp.1-2 (numeric line p.1; symbol cipher p.2); R4333 p.3; R4338 p.1: R4284: p.1 one block of 5 lines of comma-separated numbers (~120 groups); p.2 symbol cipher in about 5 short blocks plus a pencil note 'Chifferdaru' (cipher key box). R4333 p.3: continuous numeric cipher, ~20 lines (p.1 is a small slip with a few numbers and clear text; p.2 and p.4 are volume photos). R4338 p.1: Swedish letter of 8/18 June 1633 in clear with interlinear glossed code numbers (e.g. 1328, 3192, 3105) and decipherments written above them. No full decipherment on R4284. (checked 2026-10-30 by an LLM on the page) open that page

What is known

known checked 21 Oct 2026 Bremen letters of 1631 (R4330-R4331) deciphered in full here, key recovered from the interlinear glosses (riksarkivet1628). R4282 key recovered ciphertext-only by George Lasry (decode4282, PR #33). R4306 deciphered in part by George Lasry with CTTS and Opus 5.5, 17 Oct 2026 (sweden4306, PR #42); four code values open. R4336-R4337 (Rusdorff, London, Feb 1625) key recovered ciphertext-only by George Lasry with CTTS and Claude Opus 5.5, 21 Oct 2026 (rusdorff1625, PR #72); codes 628 and 701 open.

open All cipher passages; surveyed only (targets/rusdorff1628). The rusdorff1625 key does not fit R4333.

written up rusdorff1625 · sweden4306 · riksarkivet1628 · riksarkivet4284

History and prior art. DECODE R4284–R4341, 8 records in four different ciphers, each its own entry since the one-key split of 14 Oct 2026. Viewed 21 Sept 2026. The two Bremen letters of 1631 (R4330–R4331, riksarkivet1628.html) are read and removed from this entry; R4282 was deciphered by George Lasry (decode4282.html). R4306: contributed partial Dutch decipherment by George Lasry, transcribed with CTTS then solved with Opus 5.5 (17 Oct 2026; sweden4306.html, which also records this project's failed attempt of 21 Sept 2026); pencilled 1632? and Amsterdam attribution remain qualified, four code identities open. R4336–R4337 turned out to be Rusdorff's London letters of February 1625 in a homophonic cipher with an alphabetical nomenclator; key recovered from the ciphertext by George Lasry (21 Oct 2026, PR #72; rusdorff1625.html) and removed from this entry. Open: R4284 (Latin 1628, Camerarius docket; riksarkivet4284.html) — attacked with Latin annealing and against two box keys, not broken; R4333–R4335 (Rusdorff → Oxenstierna 1628, another cipher; rusdorff1628.html) and R4338–R4341 (E 708, Swedish, June 1633, not 1646; glossed in part at the time; oxenstierna1633.html) surveyed only. Narrowed to the unread part and restored 2 Nov 2026.

Outcome so far. In progress here, in targets/oxenstierna1633/ and targets/riksarkivet4284/ and targets/rusdorff1628/ (earlier: attempted, open).

Check first. Fetch the images and the key record(s); test the key on the first lines.

Scores

Importance
3 of 5
Solvability
4 of 5
Difficulty
3 of 5
Class A
a sibling letter with a decipherment is in the same volume or series, so matching it is the first move
Note
Scored by rule from DECODE metadata (class from key signals, solvability from key, length and language, importance from the correspondents); not yet reviewed by hand.

Send a result

A reading, a partial reading, a transcription, or a source that shows it was read long ago: all of it counts and is credited to you on the site.

Open a solution issueOther kinds of reportHow credit works← All unsolved ciphers