Flak Command Black Forest, 17 May 1940

At a glanceKey from adjacent plaintext · complete

The messages: Two radio messages of 17 May 1940 of the Flugabwehrkommando Schwarzwald: frame 0993 in four parts (Luftgaukommando VII to the command) and frames 1025–1027 in two parts (the command itself), 1,023 letters of text.
Where: National Archives, Record Group 242, microfilm T405 roll 9 (NAID 332033680); catalogue 704.
The cipher: Double columnar transposition with a 24-column and a 28-column key; the first group of each part is an indicator.
How it was read: Harumi-Matsuba, with Claude Fable 5.1, fitted the plaintext of parts 3 and 4 of frame 0993 to the recipient’s fair copy and ran known-plaintext searches for the keys from part 4 (Claude Sonnet and OpenAI Codex served as image judges and second reader); the project decrypted all six parts with its own code and got his letter strings (with part 3 put in order, as he describes), against a random-key trigram control (66 against a best of 19). The images were not seen here.
What they say: Transfer of Flak platoons of Reserve Light Flak Battalion 932 and an anti-aircraft machine-gun company to the command and a report of one platoon in position west of Tüllingen.
Still open: Seven letters are wrong as plaintext; the transcriptions were made by an AI and no person has checked them against the images; the other days of the reel are unread.
Credit: The keys, the transcriptions and the reading are Harumi-Matsuba’s (issue #364), with Anthropic Claude and an OpenAI Codex second reader; the plaintexts are the contemporary fair copy and teleprinter original.

01 The messages

Two radio messages of 17 May 1940 from the file of the Luftgaukommando VII (Munich) and its Flak units: National Archives, Record Group 242, microfilm T405 roll 9 (NAID 332033680). The first, frame 0993, is a typed teleprinter copy sent to the Flugabwehrkommando Schwarzwald in four parts; the recipient’s hand-written fair copy is on frames 0994–0995. The second, frames 1025–1027, is a hand-written radio form of the Flugabwehrkommando Schwarzwald itself, in two parts; its teleprinter original is on frame 1024. Both are in five-letter groups. The ledger (catalogue 704) listed the whole reel, about 70 such forms (the catalogue’s estimate), as a test bed for a double transposition. Harumi-Matsuba read these two with Anthropic Claude and sent the transcriptions, the keys and the reading; the project could not reach the scans and checked the keys against his transcriptions.

02 The cipher and the keys

A double columnar transposition. The plaintext is written in rows in a grid 24 columns wide and read off by columns in the order of a numeric key; the result is written in a grid 28 columns wide and read off the same way. The first group of each part is an indicator and not text. The keys for 17 May 1940:

Grid	Key
24 columns	15 12 20 8 17 4 22 9 19 2 16 11 5 21 10 3 14 24 7 13 1 6 18 23
28 columns	24 17 10 21 6 18 27 1 22 16 7 25 11 2 20 23 4 8 13 19 28 14 5 9 15 3 26 12

The contributor fixed the plaintext of parts 3 and 4 of frame 0993 from the recipient’s fair copy, by fitting spellings to the letter counts, and found the keys with known-plaintext searches of his own from part 4. The other parts and the whole of the second message were then decrypted with the same two keys, but the transcriptions were not left untouched: part 3 decrypts only with its lines 2 and 3 put back in order and letter 113 read T, and the contributor corrected some letters of the hand-written transcription (and three Q/O letters of part 4) against the images after decrypting, so the transcriptions are partly informed by the decryption. The same system, with other keys, is on the 1939 exercise message and key card of frames 349–350, which he used to test his tools.

Checked here, with an own implementation written from the description: the two keys undo the six parts of his transcriptions to the six strings of his plaintext.txt, letter for letter (1,023 letters). A count of frequent German trigrams gives 66 for these decryptions against a mean of 8.9 and a best of 19 for 300 random pairs of keys of the same lengths. That shows the keys make German, not how many letters are right.

03 The reading

G.Kdos. 1.) Flakgruppe Friedrichshafen gibt an Flugabwehrkommando Schwarzwald ab: 1. und 3. Zug der 3. Batterie Res. Lei. Flakabteilung 932 (Herbertingen). Die beiden Züge werden durch Flugabwehrkommando Schwarzwald transportiert und gem. fernmündlicher Besprechung eingesetzt. 2.) Flakgruppe Friedrichshafen setzt 3. Zug Fla. M.G. Res. Komp. 304 (Sigmaringen) beim Schutzobjekt Herbertingen ein. […] Die neuen Stellungen und Feuerbereitschaft zu melden.

Geheime Kommandosache. Am 16.5.40 wurde dem Flgabw.Kdo. Schwarzwald der I. Zug 2./932 (2 cm) von Flakgruppe Friedrichshafen zugeteilt. Der Zug ist seit 22.30 Uhr in Stellung 3031 westl. Tüllingen feuerbereit. Er ist Abt. 942 unterstellt.

That is the contributor’s division of the letter strings into words, with his spelling conventions (X between words and names, Q for CH, digits spelled out, KLAMMER for a bracket). In English: Flak Group Friedrichshafen hands over to the Flak Command Black Forest the 1st and 3rd platoons of the 3rd battery of Reserve Light Flak Battalion 932 (Herbertingen), to be moved by the command and employed as agreed by telephone, and places the 3rd platoon of Anti-aircraft Machine-gun Reserve Company 304 (Sigmaringen) at the protected object Herbertingen; new positions and readiness to fire are to be reported. In the second message the 1st platoon of 2./932 (2 cm) was assigned to the command on 16 May, has been ready to fire since 22.30 hours in position 3031 west of Tüllingen, and is subordinated to Battalion 942. Both messages exist in a contemporary form beside the cipher (the fair copy and the teleprinter original), so no unknown text was read here; what is new is the key of the day.

04 What remains uncertain

Seven of the 1,023 letters are wrong as plaintext (about 0.7%): five in the typed text of frame 0993 (BATBERIE, TRANSPORTIWRT, FERNNUENDLIQER, and an X and a Q in part 4), which the contributor takes for errors of the sender or the relay, and two in the hand-written message (VIEENULL, GHDOS), where the handwriting cannot settle e or R, h or k.
The transcriptions were made by an AI from the NARA frames; the contributor’s blind second reading by another model agrees on 99.2% of frame 0993 and 93.8% to 95.4% of frames 1025–1027 (his figures). No person has compared them with the images, and the project did not see the images.
How the key follows from the indicator group is not known; the 1939 key card lists four three-letter indicator groups but no rule for this day.
The other days of the reel (9 April, 3, 8, 16 and 20 May, 4 June and others) have other keys and are unread; catalogue 704 stays open for them.
No statistical validation by the project’s n-gram test, which is made for substitutions; the trigram control above stands in for it.

Full texts

The transcription and the decryption of every document on this page, so that the reading can be used and checked. Short files are shown here; all are in the repository.

Frame 0993: Luftgaukommando VII to Flugabwehrkommando Schwarzwald, 17 May 1940

A secret command message: Flakgruppe Friedrichshafen hands over to Flugabwehrkommando Schwarzwald the 1st and 3rd platoons of the 3rd battery of Reserve Light Flak Battalion 932 (Herbertingen), which the Flugabwehrkommando will transport and employ as arranged by telephone, and places the 3rd platoon of Anti-aircraft Machine-gun Reserve Company 304 (Sigmaringen) at the protected object Herbertingen; new positions and readiness to fire are to be reported.

Transcription

ciphertext_0993.txt

# NARA RG 242, T405 roll 9, frame 0993. Teleprinter copy of a radio message in four parts, 17 May 1940
# (SMU 0113 17/5 1500, to Flugabw. Kdo. Schwarzwald; header "G-KDOS- 4 TEILE", part lengths 179, 178, 167, 130).
# Transcribed from the frame image as typed, ten groups per line as on the page. The first group of each part is the key indicator group.
# Notes:
# - Part 3 is given in the order of the page. Lines 2 and 3 of part 3 are interchanged on the page (see docs/METHOD); decrypt.py puts them back.
# - Part 3, group 22 (EDIMN): the third letter was first read as I (a vertical bar with short bars at top and bottom); it is T (see docs/METHOD).
# This file keeps the first reading; decrypt.py applies the correction.
# - Part 4, group 1: all five letters are blotted out by the recipient; the fourth letter is illegible (a round letter).
# - In part 4 three letters first read as Q are O (groups 4, 13, 26): pen marks under the letters looked like the tail of a Q. This file has the corrected letters.
[part 1]
ALCER TEBDA IGFIP XESWB ENAKA NRXZE ONRAX EAUFS BLLDC MEEOM
DGLXF PKKNK NRRAI EPRRD OAUIX XBUMX EWGXT XIETG GRARL EDANL
ZBBES MAXHM XRWAP MESGX ISLAO EZOXP EFRXI UILUI NHHEN XNLFR
TEDTH DURSE RAICE DKWXU LNKDE DSRK
[part 2]
HENYZ NXRKN NPHOE RNNRA GEHOC EXMUE IHENM EQAHD EDSGD EXWWU
MESSE BBATN WAZEP ISZAR RFRKL EPANB POUIG EREGN ZTDGG UMOAR
AAERW TFTET LZENW XTSIW UILMR EEHDR RUBFN EQKIG TDDEE URRNN
RLLSD QIXDF ENFME MCXER XEIRX XKL
[part 3]
WOLQR ELXTL ELRNE TAPRX MEHUE DTEIX EIEQD FIAGR FNSRM RHLXK
PUFLL KRTGO XIMDV AEGFX RSNAR XREOH NEXBN KSXGU ZEERR EZSAB
LUUGE GMKXA EDIMN MONUM MQPCZ EIRRP SIARN INITL BTIEE EKGXR
UDXST IXNEI NXXEJ NS
[part 4]
SOD?X TFXXX ZRMZM IOVUX UNQIR MLEFQ MXNLB XESDI NEURN TSXXE
SNSNS QEFOS XOOXK TXKRR REQGD RXEBP EADEA SMNEE TWTTO TNLWX
IUFUX RDUFN LNAIA GOOXI EAUZE EIONO

Decryption

plaintext.txt

0993 part 1 174 GKDOSXERSTENSKLAMMERFLAKGRUPPEXFRIEDRICHSHAFENXGIBTANFLUGABWEHRKOMMANDOXSCHWARZWALDXABDOPPELPUNKTXEINSXUNDXDREIXZUGDERXDREIXBATBERIEXRESXLEIXFLAKABTEILUNGXNEUNDREIZWOXKLAMMER
0993 part 2 173 XHERBERTINGENXKLAMMERXDIEBEIDENZUEGEWERDENDURQFLUGABWEHRKOMMANDOXSCHWARZWALDXTRANSPORTIWRTUNDGEMXFERNNUENDLIQERBESPREQUNGEINGESETZTXZWOTENSKLAMMERFLAKGRUPPEXFRIEDRICHSHAFENX
0993 part 3 162 SETZTXDREIXZUGFLAXMXGXRESXKOMPXDREINULLVIERXKLAMMERXSIGMARINGENXKLAMMERBEIMSQUTZOBJEKTXHERBERTINGENXEINXTRANSPORTDURQFLAKGRUPPEXFRIEDRICHSHAFENXDIENEUENSTELLUNGEN
0993 part 4 125 UNDFEUERBEREITSXAFTZUMELDENXLUFTGAUKOMMANDOXROEMXSIEBENXSTRIQROEMXEINSXANTONXOPXZWOXNRXZWOAQTFUENFEINSXSTRIQXVIERNULLXGXKDOSQ
1025 part 1 200 GEHEIMEKOMMANDOSAQEXAMXEINSSEQSXFUENFXVIERNULLXWURDEDEMXFLGABWXKDOXSCHWARZWALDDERXROEMXEINSXZUGXZWOXSTRIQXNEUNDREIZWOXKLAMMERXZWOXCENTIMETERKLAMMERVONFLAKGRUPPEXFRIEDRICHSHAFENXZUGETEILTXDERZUGISTSEIT
1027 part 2 189 ZWOZWODREINULLXUHRINSTELLUNGXDREINULLDREIEINSXWESTLXTUELLINGENXFEUERBEREITXERISTABTXNEUNVIERZWOXUNTERSTELLTXFLGABWKDOXSCHWARZWALDXROEMXEINSXCAESARXNRXFRITZXEINSSEQSEINSXSTRIQXVIEENULLXGHDOS

Reading

contributor_reading.md

# Reading

The letter strings obtained by decrypting with the keys are in `data/plaintext.txt`. Below they are divided into words and then turned back into ordinary writing.
X is the separator, Q stands for CH. Bold letters are letters that are wrong as plaintext (the cipher text has that letter).

## Frame 0993 (Luftgaukommando VII to Flugabwehrkommando Schwarzwald, 17 May 1940, four parts)

1. `GKDOS X ERSTENS KLAMMER FLAKGRUPPE X FRIEDRICHSHAFEN X GIBT AN FLUGABWEHRKOMMANDO X SCHWARZWALD X AB DOPPELPUNKT X EINS X UND X DREI X ZUG DER X DREI X BAT`**`B`**`ERIE X RES X LEI X FLAKABTEILUNG X NEUNDREIZWO X KLAMMER`
2. `X HERBERTINGEN X KLAMMER X DIE BEIDEN ZUEGE WERDEN DURQ FLUGABWEHRKOMMANDO X SCHWARZWALD X TRANSPORTI`**`W`**`RT UND GEM X FERN`**`N`**`UENDLIQER BESPREQUNG EINGESETZT X ZWOTENS KLAMMER FLAKGRUPPE X FRIEDRICHSHAFEN X`
3. `SETZT X DREI X ZUG FLA X M X G X RES X KOMP X DREINULLVIER X KLAMMER X SIGMARINGEN X KLAMMER BEIM SQUTZOBJEKT X HERBERTINGEN X EIN X TRANSPORT DURQ FLAKGRUPPE X FRIEDRICHSHAFEN X DIE NEUEN STELLUNGEN`
4. `UND FEUERBEREITS`**`X`**`AFT ZU MELDEN X LUFTGAUKOMMANDO X ROEM X SIEBEN X STRIQ ROEM X EINS X ANTON X OP X ZWO X NR X ZWOAQTFUENFEINS X STRIQ X VIERNULL X G X KDOS `**`Q`**

In ordinary writing:

> G.Kdos. 1.) Flakgruppe Friedrichshafen gibt an Flugabwehrkommando Schwarzwald ab: 1. und 3. Zug der 3. Batterie Res. Lei. Flakabteilung 932 (Herbertingen). Die beiden Züge werden durch Flugabwehrkommando Schwarzwald transportiert und gem. fernmündlicher Besprechung eingesetzt. 2.) Flakgruppe Friedrichshafen setzt 3. Zug Fla. M.G. Res. Komp. 304 (Sigmaringen) beim Schutzobjekt Herbertingen ein. Transport durch Flakgruppe Friedrichshafen. Die neuen Stellungen und Feuerbereitschaft zu melden. Luftgaukommando VII/Ia op 2 Nr. 2851/40 g.Kdos.

This has the same content as the recipient's fair copy (frames 0994-0995).

## Frames 1025-1027 (from Flugabwehrkommando Schwarzwald Ic, 17 May 1940, two parts)

1. `GEHEIME KOMMANDOSAQE X AM X EINSSEQS X FUENF X VIERNULL X WURDE DEM X FLGABW X KDO X SCHWARZWALD DER X ROEM X EINS X ZUG X ZWO X STRIQ X NEUNDREIZWO X KLAMMER X ZWO X CENTIMETER KLAMMER VON FLAKGRUPPE X FRIEDRICHSHAFEN X ZUGETEILT X DER ZUG IST SEIT`
2. `ZWOZWODREINULL X UHR IN STELLUNG X DREINULLDREIEINS X WESTL X TUELLINGEN X FEUERBEREIT X ER IST ABT X NEUNVIERZWO X UNTERSTELLT X FLGABWKDO X SCHWARZWALD X ROEM X EINS X CAESAR X NR X FRITZ X EINSSEQSEINS X STRIQ X VIE`**`E`**`NULL X G`**`H`**`DOS`

In ordinary writing:

> Geheime Kommandosache. Am 16.5.40 wurde dem Flgabw.Kdo. Schwarzwald der I. Zug 2./932 (2 cm) von Flakgruppe Friedrichshafen zugeteilt. Der Zug ist seit 22.30 Uhr in Stellung 3031 westl. Tüllingen feuerbereit. Er ist Abt. 942 unterstellt. Flgabw.Kdo. Schwarzwald Ic Nr. F 161/40 g.Kdos.

This has the same content as the teleprinter message of the same day (frame 1024).

## Spelling conventions (as seen in these two messages)

- X separates words. It stands before and after names, numbers and abbreviations; ordinary running words are written together (`DIEBEIDENZUEGEWERDEN`).
- CH is written Q (`DURQ`, `SQUTZOBJEKT`, `STRIQ`); names keep CH (`FRIEDRICHSHAFEN`, `SCHWARZWALD`).
- Numbers are spelled digit by digit and run together (`NEUNDREIZWO` = 932, `ZWOAQTFUENFEINS` = 2851); 2 is ZWO.
- "1.)" and "2.)" are `ERSTENS KLAMMER` and `ZWOTENS KLAMMER`; brackets are `KLAMMER`, the colon is `DOPPELPUNKT`, the slash is `STRIQ`.
- Roman numerals are preceded by `ROEM` (`ROEM SIEBEN` = VII, `ROEM EINS` = I). Single letters are spelled by name (`ANTON` = a, `CAESAR` = c, `FRITZ` = F).
- The first five-letter group of each part is the key indicator group and is not part of the text. The parts end at word boundaries.

## Wrong letters (7 of 1,023)

| Place | Plaintext | Cipher-text letter | Remark |
|---|---|---|---|
| 0993 part 1 | BAT**B**ERIE | letter 8 (TE**B**DA) | typed B; an error for T |
| 0993 part 2 | TRANSPORTI**W**RT | letter 49 (EXW**W**U) | typed W; an error for E |
| 0993 part 2 | FERN**N**UENDLIQER | letter 18 (RN**N**RA) | typed N; an error for M |
| 0993 part 4 | FEUERBEREITS**X**AFT and the final **Q** | letter 32 (M**X**NLB) and letter 30 (MLEF**Q**) | exchanging the two letters gives SQAFT and a final X |
| 1027 | VIE**E**NULL | letter 137 (R**E**TEZ) | written e; an error for R |
| 1027 | G**H**DOS | letter 194 (IZN**H**) | h and k are close in this hand; may be K |

The five letters in frame 0993 are those letters in the typed cipher text, also when enlarged. We take them to be errors made in enciphering or in relaying the message (there is nothing to check this against).

Translation

contributor_reading.md

# Reading

The letter strings obtained by decrypting with the keys are in `data/plaintext.txt`. Below they are divided into words and then turned back into ordinary writing.
X is the separator, Q stands for CH. Bold letters are letters that are wrong as plaintext (the cipher text has that letter).

## Frame 0993 (Luftgaukommando VII to Flugabwehrkommando Schwarzwald, 17 May 1940, four parts)

1. `GKDOS X ERSTENS KLAMMER FLAKGRUPPE X FRIEDRICHSHAFEN X GIBT AN FLUGABWEHRKOMMANDO X SCHWARZWALD X AB DOPPELPUNKT X EINS X UND X DREI X ZUG DER X DREI X BAT`**`B`**`ERIE X RES X LEI X FLAKABTEILUNG X NEUNDREIZWO X KLAMMER`
2. `X HERBERTINGEN X KLAMMER X DIE BEIDEN ZUEGE WERDEN DURQ FLUGABWEHRKOMMANDO X SCHWARZWALD X TRANSPORTI`**`W`**`RT UND GEM X FERN`**`N`**`UENDLIQER BESPREQUNG EINGESETZT X ZWOTENS KLAMMER FLAKGRUPPE X FRIEDRICHSHAFEN X`
3. `SETZT X DREI X ZUG FLA X M X G X RES X KOMP X DREINULLVIER X KLAMMER X SIGMARINGEN X KLAMMER BEIM SQUTZOBJEKT X HERBERTINGEN X EIN X TRANSPORT DURQ FLAKGRUPPE X FRIEDRICHSHAFEN X DIE NEUEN STELLUNGEN`
4. `UND FEUERBEREITS`**`X`**`AFT ZU MELDEN X LUFTGAUKOMMANDO X ROEM X SIEBEN X STRIQ ROEM X EINS X ANTON X OP X ZWO X NR X ZWOAQTFUENFEINS X STRIQ X VIERNULL X G X KDOS `**`Q`**

In ordinary writing:

> G.Kdos. 1.) Flakgruppe Friedrichshafen gibt an Flugabwehrkommando Schwarzwald ab: 1. und 3. Zug der 3. Batterie Res. Lei. Flakabteilung 932 (Herbertingen). Die beiden Züge werden durch Flugabwehrkommando Schwarzwald transportiert und gem. fernmündlicher Besprechung eingesetzt. 2.) Flakgruppe Friedrichshafen setzt 3. Zug Fla. M.G. Res. Komp. 304 (Sigmaringen) beim Schutzobjekt Herbertingen ein. Transport durch Flakgruppe Friedrichshafen. Die neuen Stellungen und Feuerbereitschaft zu melden. Luftgaukommando VII/Ia op 2 Nr. 2851/40 g.Kdos.

This has the same content as the recipient's fair copy (frames 0994-0995).

## Frames 1025-1027 (from Flugabwehrkommando Schwarzwald Ic, 17 May 1940, two parts)

1. `GEHEIME KOMMANDOSAQE X AM X EINSSEQS X FUENF X VIERNULL X WURDE DEM X FLGABW X KDO X SCHWARZWALD DER X ROEM X EINS X ZUG X ZWO X STRIQ X NEUNDREIZWO X KLAMMER X ZWO X CENTIMETER KLAMMER VON FLAKGRUPPE X FRIEDRICHSHAFEN X ZUGETEILT X DER ZUG IST SEIT`
2. `ZWOZWODREINULL X UHR IN STELLUNG X DREINULLDREIEINS X WESTL X TUELLINGEN X FEUERBEREIT X ER IST ABT X NEUNVIERZWO X UNTERSTELLT X FLGABWKDO X SCHWARZWALD X ROEM X EINS X CAESAR X NR X FRITZ X EINSSEQSEINS X STRIQ X VIE`**`E`**`NULL X G`**`H`**`DOS`

In ordinary writing:

> Geheime Kommandosache. Am 16.5.40 wurde dem Flgabw.Kdo. Schwarzwald der I. Zug 2./932 (2 cm) von Flakgruppe Friedrichshafen zugeteilt. Der Zug ist seit 22.30 Uhr in Stellung 3031 westl. Tüllingen feuerbereit. Er ist Abt. 942 unterstellt. Flgabw.Kdo. Schwarzwald Ic Nr. F 161/40 g.Kdos.

This has the same content as the teleprinter message of the same day (frame 1024).

## Spelling conventions (as seen in these two messages)

- X separates words. It stands before and after names, numbers and abbreviations; ordinary running words are written together (`DIEBEIDENZUEGEWERDEN`).
- CH is written Q (`DURQ`, `SQUTZOBJEKT`, `STRIQ`); names keep CH (`FRIEDRICHSHAFEN`, `SCHWARZWALD`).
- Numbers are spelled digit by digit and run together (`NEUNDREIZWO` = 932, `ZWOAQTFUENFEINS` = 2851); 2 is ZWO.
- "1.)" and "2.)" are `ERSTENS KLAMMER` and `ZWOTENS KLAMMER`; brackets are `KLAMMER`, the colon is `DOPPELPUNKT`, the slash is `STRIQ`.
- Roman numerals are preceded by `ROEM` (`ROEM SIEBEN` = VII, `ROEM EINS` = I). Single letters are spelled by name (`ANTON` = a, `CAESAR` = c, `FRITZ` = F).
- The first five-letter group of each part is the key indicator group and is not part of the text. The parts end at word boundaries.

## Wrong letters (7 of 1,023)

| Place | Plaintext | Cipher-text letter | Remark |
|---|---|---|---|
| 0993 part 1 | BAT**B**ERIE | letter 8 (TE**B**DA) | typed B; an error for T |
| 0993 part 2 | TRANSPORTI**W**RT | letter 49 (EXW**W**U) | typed W; an error for E |
| 0993 part 2 | FERN**N**UENDLIQER | letter 18 (RN**N**RA) | typed N; an error for M |
| 0993 part 4 | FEUERBEREITS**X**AFT and the final **Q** | letter 32 (M**X**NLB) and letter 30 (MLEF**Q**) | exchanging the two letters gives SQAFT and a final X |
| 1027 | VIE**E**NULL | letter 137 (R**E**TEZ) | written e; an error for R |
| 1027 | G**H**DOS | letter 194 (IZN**H**) | h and k are close in this hand; may be K |

The five letters in frame 0993 are those letters in the typed cipher text, also when enlarged. We take them to be errors made in enciphering or in relaying the message (there is nothing to check this against).

Frames 1025-1027: Flugabwehrkommando Schwarzwald Ic, 17 May 1940

A secret command message: on 16 May 1940 the 1st platoon of 2./932 (2 cm) of Flakgruppe Friedrichshafen was assigned to Flugabwehrkommando Schwarzwald; the platoon has been ready to fire since 22.30 hrs in position 3031 west of Tüllingen and is subordinated to Battalion 942.

Transcription

ciphertext_1025_1027.txt

# NARA RG 242, T405 roll 9, frames 1025-1026 (part 1, 205 letters; the last group is on the back of the sheet, frame 1026) and 1027 (part 2, 194 letters).
# Hand-written radio message form, outgoing message of Flugabwehrkommando Schwarzwald, 17 May 1940 (radio version of the teleprinter message on frame 1024).
# Four groups per row as on the form. The first group of each part is the key indicator group.
# Letters corrected after decryption by a second look at the image are marked in docs/METHOD (g with a cross-stroke on the descender = q, six letters; o -> c, one letter).
[part 1]
kdqxd ebver aexme emrfq
zpess rsulx raeen xieoi
oeaeg wtlnk zmodi xnunx
wixdd dmucn soxxm fxexm
gfzdr aiodn kltsc hamex
riwmm sialr quutr azmlx
eaesw tknxr igped oxgsx
klihe qezfe elxnt mehnz
rszhw igoia txnea xixux
wcfre eedrs oefeg uktrr
vwudl
[part 2]
lmlgr snrnn dexxr rzxrd
qgsrl uxrxx xisel vilol
ruhlf ietst oceax sttwx
kubem bxeni etltl nrlsi
zxzsr fiuor lneen ereos
liwin elrni xswxx snscl
ntaax nighr detev retez
qewui aifew uieew xdwau
ssgol eebue ntnsu dxgod
eertx llaix iznh

Decryption

plaintext.txt

0993 part 1 174 GKDOSXERSTENSKLAMMERFLAKGRUPPEXFRIEDRICHSHAFENXGIBTANFLUGABWEHRKOMMANDOXSCHWARZWALDXABDOPPELPUNKTXEINSXUNDXDREIXZUGDERXDREIXBATBERIEXRESXLEIXFLAKABTEILUNGXNEUNDREIZWOXKLAMMER
0993 part 2 173 XHERBERTINGENXKLAMMERXDIEBEIDENZUEGEWERDENDURQFLUGABWEHRKOMMANDOXSCHWARZWALDXTRANSPORTIWRTUNDGEMXFERNNUENDLIQERBESPREQUNGEINGESETZTXZWOTENSKLAMMERFLAKGRUPPEXFRIEDRICHSHAFENX
0993 part 3 162 SETZTXDREIXZUGFLAXMXGXRESXKOMPXDREINULLVIERXKLAMMERXSIGMARINGENXKLAMMERBEIMSQUTZOBJEKTXHERBERTINGENXEINXTRANSPORTDURQFLAKGRUPPEXFRIEDRICHSHAFENXDIENEUENSTELLUNGEN
0993 part 4 125 UNDFEUERBEREITSXAFTZUMELDENXLUFTGAUKOMMANDOXROEMXSIEBENXSTRIQROEMXEINSXANTONXOPXZWOXNRXZWOAQTFUENFEINSXSTRIQXVIERNULLXGXKDOSQ
1025 part 1 200 GEHEIMEKOMMANDOSAQEXAMXEINSSEQSXFUENFXVIERNULLXWURDEDEMXFLGABWXKDOXSCHWARZWALDDERXROEMXEINSXZUGXZWOXSTRIQXNEUNDREIZWOXKLAMMERXZWOXCENTIMETERKLAMMERVONFLAKGRUPPEXFRIEDRICHSHAFENXZUGETEILTXDERZUGISTSEIT
1027 part 2 189 ZWOZWODREINULLXUHRINSTELLUNGXDREINULLDREIEINSXWESTLXTUELLINGENXFEUERBEREITXERISTABTXNEUNVIERZWOXUNTERSTELLTXFLGABWKDOXSCHWARZWALDXROEMXEINSXCAESARXNRXFRITZXEINSSEQSEINSXSTRIQXVIEENULLXGHDOS

Reading

contributor_reading.md

# Reading

The letter strings obtained by decrypting with the keys are in `data/plaintext.txt`. Below they are divided into words and then turned back into ordinary writing.
X is the separator, Q stands for CH. Bold letters are letters that are wrong as plaintext (the cipher text has that letter).

## Frame 0993 (Luftgaukommando VII to Flugabwehrkommando Schwarzwald, 17 May 1940, four parts)

1. `GKDOS X ERSTENS KLAMMER FLAKGRUPPE X FRIEDRICHSHAFEN X GIBT AN FLUGABWEHRKOMMANDO X SCHWARZWALD X AB DOPPELPUNKT X EINS X UND X DREI X ZUG DER X DREI X BAT`**`B`**`ERIE X RES X LEI X FLAKABTEILUNG X NEUNDREIZWO X KLAMMER`
2. `X HERBERTINGEN X KLAMMER X DIE BEIDEN ZUEGE WERDEN DURQ FLUGABWEHRKOMMANDO X SCHWARZWALD X TRANSPORTI`**`W`**`RT UND GEM X FERN`**`N`**`UENDLIQER BESPREQUNG EINGESETZT X ZWOTENS KLAMMER FLAKGRUPPE X FRIEDRICHSHAFEN X`
3. `SETZT X DREI X ZUG FLA X M X G X RES X KOMP X DREINULLVIER X KLAMMER X SIGMARINGEN X KLAMMER BEIM SQUTZOBJEKT X HERBERTINGEN X EIN X TRANSPORT DURQ FLAKGRUPPE X FRIEDRICHSHAFEN X DIE NEUEN STELLUNGEN`
4. `UND FEUERBEREITS`**`X`**`AFT ZU MELDEN X LUFTGAUKOMMANDO X ROEM X SIEBEN X STRIQ ROEM X EINS X ANTON X OP X ZWO X NR X ZWOAQTFUENFEINS X STRIQ X VIERNULL X G X KDOS `**`Q`**

In ordinary writing:

> G.Kdos. 1.) Flakgruppe Friedrichshafen gibt an Flugabwehrkommando Schwarzwald ab: 1. und 3. Zug der 3. Batterie Res. Lei. Flakabteilung 932 (Herbertingen). Die beiden Züge werden durch Flugabwehrkommando Schwarzwald transportiert und gem. fernmündlicher Besprechung eingesetzt. 2.) Flakgruppe Friedrichshafen setzt 3. Zug Fla. M.G. Res. Komp. 304 (Sigmaringen) beim Schutzobjekt Herbertingen ein. Transport durch Flakgruppe Friedrichshafen. Die neuen Stellungen und Feuerbereitschaft zu melden. Luftgaukommando VII/Ia op 2 Nr. 2851/40 g.Kdos.

This has the same content as the recipient's fair copy (frames 0994-0995).

## Frames 1025-1027 (from Flugabwehrkommando Schwarzwald Ic, 17 May 1940, two parts)

1. `GEHEIME KOMMANDOSAQE X AM X EINSSEQS X FUENF X VIERNULL X WURDE DEM X FLGABW X KDO X SCHWARZWALD DER X ROEM X EINS X ZUG X ZWO X STRIQ X NEUNDREIZWO X KLAMMER X ZWO X CENTIMETER KLAMMER VON FLAKGRUPPE X FRIEDRICHSHAFEN X ZUGETEILT X DER ZUG IST SEIT`
2. `ZWOZWODREINULL X UHR IN STELLUNG X DREINULLDREIEINS X WESTL X TUELLINGEN X FEUERBEREIT X ER IST ABT X NEUNVIERZWO X UNTERSTELLT X FLGABWKDO X SCHWARZWALD X ROEM X EINS X CAESAR X NR X FRITZ X EINSSEQSEINS X STRIQ X VIE`**`E`**`NULL X G`**`H`**`DOS`

In ordinary writing:

> Geheime Kommandosache. Am 16.5.40 wurde dem Flgabw.Kdo. Schwarzwald der I. Zug 2./932 (2 cm) von Flakgruppe Friedrichshafen zugeteilt. Der Zug ist seit 22.30 Uhr in Stellung 3031 westl. Tüllingen feuerbereit. Er ist Abt. 942 unterstellt. Flgabw.Kdo. Schwarzwald Ic Nr. F 161/40 g.Kdos.

This has the same content as the teleprinter message of the same day (frame 1024).

## Spelling conventions (as seen in these two messages)

- X separates words. It stands before and after names, numbers and abbreviations; ordinary running words are written together (`DIEBEIDENZUEGEWERDEN`).
- CH is written Q (`DURQ`, `SQUTZOBJEKT`, `STRIQ`); names keep CH (`FRIEDRICHSHAFEN`, `SCHWARZWALD`).
- Numbers are spelled digit by digit and run together (`NEUNDREIZWO` = 932, `ZWOAQTFUENFEINS` = 2851); 2 is ZWO.
- "1.)" and "2.)" are `ERSTENS KLAMMER` and `ZWOTENS KLAMMER`; brackets are `KLAMMER`, the colon is `DOPPELPUNKT`, the slash is `STRIQ`.
- Roman numerals are preceded by `ROEM` (`ROEM SIEBEN` = VII, `ROEM EINS` = I). Single letters are spelled by name (`ANTON` = a, `CAESAR` = c, `FRITZ` = F).
- The first five-letter group of each part is the key indicator group and is not part of the text. The parts end at word boundaries.

## Wrong letters (7 of 1,023)

| Place | Plaintext | Cipher-text letter | Remark |
|---|---|---|---|
| 0993 part 1 | BAT**B**ERIE | letter 8 (TE**B**DA) | typed B; an error for T |
| 0993 part 2 | TRANSPORTI**W**RT | letter 49 (EXW**W**U) | typed W; an error for E |
| 0993 part 2 | FERN**N**UENDLIQER | letter 18 (RN**N**RA) | typed N; an error for M |
| 0993 part 4 | FEUERBEREITS**X**AFT and the final **Q** | letter 32 (M**X**NLB) and letter 30 (MLEF**Q**) | exchanging the two letters gives SQAFT and a final X |
| 1027 | VIE**E**NULL | letter 137 (R**E**TEZ) | written e; an error for R |
| 1027 | G**H**DOS | letter 194 (IZN**H**) | h and k are close in this hand; may be K |

The five letters in frame 0993 are those letters in the typed cipher text, also when enlarged. We take them to be errors made in enciphering or in relaying the message (there is nothing to check this against).

Translation

contributor_reading.md

# Reading

The letter strings obtained by decrypting with the keys are in `data/plaintext.txt`. Below they are divided into words and then turned back into ordinary writing.
X is the separator, Q stands for CH. Bold letters are letters that are wrong as plaintext (the cipher text has that letter).

## Frame 0993 (Luftgaukommando VII to Flugabwehrkommando Schwarzwald, 17 May 1940, four parts)

1. `GKDOS X ERSTENS KLAMMER FLAKGRUPPE X FRIEDRICHSHAFEN X GIBT AN FLUGABWEHRKOMMANDO X SCHWARZWALD X AB DOPPELPUNKT X EINS X UND X DREI X ZUG DER X DREI X BAT`**`B`**`ERIE X RES X LEI X FLAKABTEILUNG X NEUNDREIZWO X KLAMMER`
2. `X HERBERTINGEN X KLAMMER X DIE BEIDEN ZUEGE WERDEN DURQ FLUGABWEHRKOMMANDO X SCHWARZWALD X TRANSPORTI`**`W`**`RT UND GEM X FERN`**`N`**`UENDLIQER BESPREQUNG EINGESETZT X ZWOTENS KLAMMER FLAKGRUPPE X FRIEDRICHSHAFEN X`
3. `SETZT X DREI X ZUG FLA X M X G X RES X KOMP X DREINULLVIER X KLAMMER X SIGMARINGEN X KLAMMER BEIM SQUTZOBJEKT X HERBERTINGEN X EIN X TRANSPORT DURQ FLAKGRUPPE X FRIEDRICHSHAFEN X DIE NEUEN STELLUNGEN`
4. `UND FEUERBEREITS`**`X`**`AFT ZU MELDEN X LUFTGAUKOMMANDO X ROEM X SIEBEN X STRIQ ROEM X EINS X ANTON X OP X ZWO X NR X ZWOAQTFUENFEINS X STRIQ X VIERNULL X G X KDOS `**`Q`**

In ordinary writing:

> G.Kdos. 1.) Flakgruppe Friedrichshafen gibt an Flugabwehrkommando Schwarzwald ab: 1. und 3. Zug der 3. Batterie Res. Lei. Flakabteilung 932 (Herbertingen). Die beiden Züge werden durch Flugabwehrkommando Schwarzwald transportiert und gem. fernmündlicher Besprechung eingesetzt. 2.) Flakgruppe Friedrichshafen setzt 3. Zug Fla. M.G. Res. Komp. 304 (Sigmaringen) beim Schutzobjekt Herbertingen ein. Transport durch Flakgruppe Friedrichshafen. Die neuen Stellungen und Feuerbereitschaft zu melden. Luftgaukommando VII/Ia op 2 Nr. 2851/40 g.Kdos.

This has the same content as the recipient's fair copy (frames 0994-0995).

## Frames 1025-1027 (from Flugabwehrkommando Schwarzwald Ic, 17 May 1940, two parts)

1. `GEHEIME KOMMANDOSAQE X AM X EINSSEQS X FUENF X VIERNULL X WURDE DEM X FLGABW X KDO X SCHWARZWALD DER X ROEM X EINS X ZUG X ZWO X STRIQ X NEUNDREIZWO X KLAMMER X ZWO X CENTIMETER KLAMMER VON FLAKGRUPPE X FRIEDRICHSHAFEN X ZUGETEILT X DER ZUG IST SEIT`
2. `ZWOZWODREINULL X UHR IN STELLUNG X DREINULLDREIEINS X WESTL X TUELLINGEN X FEUERBEREIT X ER IST ABT X NEUNVIERZWO X UNTERSTELLT X FLGABWKDO X SCHWARZWALD X ROEM X EINS X CAESAR X NR X FRITZ X EINSSEQSEINS X STRIQ X VIE`**`E`**`NULL X G`**`H`**`DOS`

In ordinary writing:

> Geheime Kommandosache. Am 16.5.40 wurde dem Flgabw.Kdo. Schwarzwald der I. Zug 2./932 (2 cm) von Flakgruppe Friedrichshafen zugeteilt. Der Zug ist seit 22.30 Uhr in Stellung 3031 westl. Tüllingen feuerbereit. Er ist Abt. 942 unterstellt. Flgabw.Kdo. Schwarzwald Ic Nr. F 161/40 g.Kdos.

This has the same content as the teleprinter message of the same day (frame 1024).

## Spelling conventions (as seen in these two messages)

- X separates words. It stands before and after names, numbers and abbreviations; ordinary running words are written together (`DIEBEIDENZUEGEWERDEN`).
- CH is written Q (`DURQ`, `SQUTZOBJEKT`, `STRIQ`); names keep CH (`FRIEDRICHSHAFEN`, `SCHWARZWALD`).
- Numbers are spelled digit by digit and run together (`NEUNDREIZWO` = 932, `ZWOAQTFUENFEINS` = 2851); 2 is ZWO.
- "1.)" and "2.)" are `ERSTENS KLAMMER` and `ZWOTENS KLAMMER`; brackets are `KLAMMER`, the colon is `DOPPELPUNKT`, the slash is `STRIQ`.
- Roman numerals are preceded by `ROEM` (`ROEM SIEBEN` = VII, `ROEM EINS` = I). Single letters are spelled by name (`ANTON` = a, `CAESAR` = c, `FRITZ` = F).
- The first five-letter group of each part is the key indicator group and is not part of the text. The parts end at word boundaries.

## Wrong letters (7 of 1,023)

| Place | Plaintext | Cipher-text letter | Remark |
|---|---|---|---|
| 0993 part 1 | BAT**B**ERIE | letter 8 (TE**B**DA) | typed B; an error for T |
| 0993 part 2 | TRANSPORTI**W**RT | letter 49 (EXW**W**U) | typed W; an error for E |
| 0993 part 2 | FERN**N**UENDLIQER | letter 18 (RN**N**RA) | typed N; an error for M |
| 0993 part 4 | FEUERBEREITS**X**AFT and the final **Q** | letter 32 (M**X**NLB) and letter 30 (MLEF**Q**) | exchanging the two letters gives SQAFT and a final X |
| 1027 | VIE**E**NULL | letter 137 (R**E**TEZ) | written e; an error for R |
| 1027 | G**H**DOS | letter 194 (IZN**H**) | h and k are close in this hand; may be K |

The five letters in frame 0993 are those letters in the typed cipher text, also when enlarged. We take them to be errors made in enciphering or in relaying the message (there is nothing to check this against).

Key: key.txt

05 Sources

National Archives, RG 242, T405 roll 9 (NAID 332033680), frames 0993–0995 and 1024–1027 (and 349–350 for the 1939 exercise key); the images are not reproduced here.
Harumi-Matsuba, issue #364 and repository Harumi-Matsuba/flak1940-public: keys, transcriptions, reading and prior-art search.

The documentation, the keys, the transcriptions, the reading and the checks are in targets/flak1940.

Cite this page

Harumi-Matsuba and Daniel Bourdeau, “Radio messages of the Flak Command Black Forest, 17 May 1940”, Cyphersolver, posted 9 November 2026, https://cyphersolver.com/flak1940.html.