Ev 1490

[tedsgran]

Help please with the playfair codeword...i have everything else but can't get anywhere working this out...

[ProfessorMaisie]

KING CHARLES

[tedsgran]

Many thanks ProfessorMaisie.....how do you work it out? I had some letters.....i.e i could see that ARL was in a column or a row and similarly with CEM but didn't know which was the row/column....and how to get the rest.

[Cloverjo]

I found this quite helpful
https://crypto.stackexchange.com/questions/35722/how-to-find-the-keyword-of-the-playfair-cipher-given-the-plaintext-and-the-ciph

[roslyn251254]

Another case then of the endgame taking longer than the grid fill!

[ProfessorMaisie]

Yes, the major input came from RA/CE - LR/EM giving ARL + CEM on two lines (as you say, tedsgran).
Another helpful pair is OW - PV with the later letters usually appearing on the bottom rows this gave the likely bottom corner as OP over VW (and the bottom row could be completed to Z). It still took a bit of trial and error to line up ARL and CEM correctly but the line from A to W clinched the PI - WA pairing.
It was too far much work after the simple grid fill for my liking but they don't come around too often I suppose.

[ProfessorMaisie]

... I added 'too' later, and it's in the wrong place but it deserves the emphasis!

[ProfessorMaisie]

...sorry, 'far' was added later (it's getting late}.