Zygalski sheets
Cryptologic technique used in World War II
The method of Zygalski sheets was a cryptologic technique used by the Polish Cipher Bureau before and during World War II, and during the war also by British cryptologists at Bletchley Park, to decrypt messages enciphered on German Enigma machines.
The Zygalski-sheet apparatus takes its name from Polish Cipher Bureau mathematician–cryptologist Henryk Zygalski, who invented it about October 1938.
Method
Zygalski's device comprised a set of 26 perforated sheets for each of the, initially, six possible sequences for inserting the three rotors into the Enigma machine's scrambler. Each sheet related to the starting position of the left (slowest-moving) rotor.
The 26 × 26 matrix represented the 676 possible starting positions of the middle and right rotors and was duplicated horizontally and vertically: a–z, a–y. The sheets were punched with holes in the positions that would allow a "female" to occur.
Polish mathematician–cryptologist Marian Rejewski writes about how the perforated-sheets device was operated:
When the sheets were superposed and moved in the proper sequence and the proper manner with respect to each other, in accordance with a strictly defined program, the number of visible apertures gradually decreased. And, if a sufficient quantity of data was available, there finally remained a single aperture, probably corresponding to the right case, that is, to the solution. From the position of the aperture one could calculate the order of the rotors, the setting of their rings, and, by comparing the letters of the cipher keys with the letters in the machine, likewise permutation S; in other words, the entire cipher key.
Like Rejewski's "card-catalog" method, developed using his "cyclometer", the Zygalski-sheet procedure was independent of the number of plugboard plug connections in the Enigma machine.
The public source identifies “Zygalski sheets” as cryptologic technique used in World War II. This brief keeps that definition visible, then builds a research path around Zygalski, sheets and Cryptologic.
Why this record matters
A short description can identify a subject without explaining its stakes. For “Zygalski sheets”, the useful work is to connect “cryptologic technique used in World War II” to the records capable of establishing context and consequence.
The record creator and administrative purpose are central evidence, because official documentation reflects both action and institutional priorities. The source revision retrieved here is dated May 11, 2026. The linked authority identifier is Q2185271. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1938.
Later summaries often reconcile disputed chronology or motive more neatly than the contemporary record permits. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Compare institutional narratives with records created by participants and affected communities. Dates and formal titles are useful anchors, but not substitutes for context.
- Event chronology
- Institutional context
- Locating named record creators
Contemporary correspondence, government or organizational records, oral histories and cited historical scholarship.
Three-step research path
- Establish the record: confirm the title “Zygalski sheets”, its source revision and the description used here.
- Expand the search: follow Zygalski sheets primary sources, Zygalski sheets archive and Zygalski research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “Zygalski sheets”?
- Which voices are present, absent or mediated by the institution?
- What chronology connects this entry to wider political or social change?
Search terms from this dossier
This entry incorporates text from “Zygalski sheets” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.