Read further · read 84.1% · ciphertext-only break · partial

“Dahka”, Cracow 1715: a sign cipher in a Polish letter

Seventeen lines of graphic signs in a Polish letter from Cracow, catalogued with no decipherment. Brice Dudout broke the substitution on the ciphertext alone and measured it on held-out lines (0.444 against 0.083, key partial): the Sandomierz deputies ask that the Crown army support their levée of 9 October 1715. 84% of 63 cipher words.

Date
1715
Read now
84.1% of the cipher tokens give sense
Write-up
dahku1715.html
Files
targets/dahku1715
Open gaps
code groups open ×2hard to read on the scanno key known

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/further/dahku1715.html

Or copy the block below into the chat. It is the whole task: the reading, every open gap, what has been tried, the steps, and how to report back.

TASK: take a partial decipherment further: “Dahka”, Cracow 1715: a sign cipher in a Polish letter
This page: https://dbourdeau.github.io/cyphersolver/further/dahku1715.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/dahku1715.html (read it first: how the text was read, the key, the reading)
  Date:       1715
  Outcome:    ciphertext-only break · partial
  Read now:   84.1% of the deciphered cipher tokens give sense (pieces below may be untouched)
  Files:      https://github.com/dbourdeau/cyphersolver/tree/main/targets/dahku1715 (NOTES.md, key, transcription, reading, scripts)

OPEN GAPS (from NOTES.md, "## Remaining gaps")
  1. [open-codes: doable now] 7 cipher words unresolved as letters: "zto", "e", "kostalacio" (d02), "kodzarzyc" (e05, a place name expected), "nadra", "zo", "a" (e05-e06; perhaps "na drugą stronę", not given by the letters) - blocker: open-codes; the key is partial and these stretches do not construe
  2. [open-codes: doable now] the framed sign N (twice) and the tied sign C (once), probably names (the subject of "chciał assistere"; a title before "prymas") - blocker: open-codes; no nomenclator for this cipher is known and the letter has only one cipher passage
  3. [illegible: needs a new source] e05 last word read on the reduced view at the page edge - blocker: illegible; a full-resolution look at the right margin of p. 3 would settle it
  4. [no-key-material: needs a new source] the key cannot be tested again on this letter (held-out lines used up) - blocker: no-key-material; another letter in the same signs is needed

ALREADY TRIED (from NOTES.md, "## Escalation")
  [x] siblings: the other scans of unit 1/338/0/1/682 were sorted (only scan 3 is in cipher); catalogue 1583 (Beck 1757) and 1593 (Forbes) of the same sweep are other systems (1583 failed with key 1196; 1593 failed)
  [x] clear-pages: no clear copy or gloss on the five scans; none known elsewhere
  [x] known-keys: AGAD 1/338/0/1/1196 ("Pour déchiffrer", Branicki circle) is a French numeric nomenclator, not this sign cipher; no other key of the fonds is known to us
  [x] print: web searches on Dahku / Cracow 1715 and the Branicki papers found no edition of this passage (3-5 Nov 2026); known.py, DECODE, Tomokiyo and Lasry: nothing
  [x] key-rebuild: key broken ciphertext-only by annealing on the training lines, frozen, measured once (partial); one sign (V) settled afterwards on a blind shape plate, for the reading only

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/dahku1715/NOTES.md in full, and the
   key, transcription and reading files it names; lang/README.md (shared language models).
   Work in targets/dahku1715/. 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/dahku1715/. 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+dahku1715&page=dahku1715.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.

Open gaps

gold can be done now: the images and the key are online, it needs only work. grey needs a new source first: a key, a better scan, an edition or the archive.

Already tried

Send a result

One closed gap counts: a code group valued, a passage re-read, a key or clear copy found elsewhere. It is credited to you on the write-up.

Open a further-reading issueOther kinds of reportHow credit works← All partial readings