The card catalogue
The Poles measured every rotor setting with the cyclometer and filed a card for each. Each morning they worked out the day’s cycle lengths from the message keys and found the card with the same lengths.
Preparing the workshop…
The day’s indicators · 80 messages
- YDVDSZ
- QUWIPU
- DDCJSQ
- QXTIYS
- OTORVE
- QAQITK
- WJCFBQ
- PLNNER
- XNFQWH
- YEEDZM
- IBBKIB
- QEEIZM
- DCHJOF
- XJIQBN
- MUOGPE
- EVKZRD
- RMLWUL
- RDAWSG
- UOWPMU
- RRGWAY
- WRBFAB
- TAGTTY
- DAZJTC
- FTVMVZ
- YEEDZM
- JQHULF
- WEMFZJ
- GUOOPE
- HDNVSR
- DUVJPZ
- QZPIQP
- ITPKVP
- IRQKAK
- LHVEDZ
- XQCQLQ
- NOQYMK
- UIIPXN
- RBBWIB
- YEEDZM
- YGJDNI
- UKMPCJ
- UWJPGI
- QUYIPV
- AEDHZA
- RMLWUL
- PDMNSJ
- FNTMWS
- FMXMUX
- MSJGHI
- MVWGRU
- NRWYAU
- BDHXSF
- ZUWAPU
- NASYTO
- YEEDZM
- TFCTJQ
- IUUKPW
- FYBMFB
- MUNGPR
- TYETFM
- EDAZSG
- CCRBOT
- LSCEHQ
- KHTCDS
- DOIJMN
- BCMXOJ
- BRRXAT
- ZULAPL
- XACQTQ
- JJOUBE
- KOVCMZ
- FKGMCY
- UVSPRO
- ITNKVR
- SNGSWY
- VOJLMI
- KQDCLA
- GDLOSL
- GZMOQJ
- LPLEKL
- Letters 1 and 4
6 6 6 6 1 1 - Letters 2 and 5
6 6 4 4 3 3 - Letters 3 and 6
9 9 2 2 1 1 1 1
- Beforehand: measure every setting once and file the cards by cycle lengths.
- Each day: work out the cycle lengths from the intercepted indicators.
- Look up the lengths: the card names the rotor order and positions.