[vertnerd]

This is a familiar concept from reading about WW2 spy stuff (Between Silk and Cyanide, for example, which I highly recommend). But what REALLY intrigues me is the typeface of the letter with its upper-case 'E' used in place of 'e'. What's up with that?

[jameshart]

That is peculiar. Brief internet search turned up a Reddit post where someone had a sample of typed text with the same odd typography: https://www.reddit.com/r/typewriters/s/f2CIY0TCm3

The suggestion that it may have been a striker from a bilingual - cyrillic typewriter that was mixed in is an interesting possibility; someone transcribing diplomatic telegrams in WWII may indeed have need of access to Cyrillic typewriters…

[andix]

Interesting idea, but both the Cyrillic and Greek capital E would be a similar size to the Latin capital E. And in both alphabets the lower case e doesn't look like a smaller capital E. It's е/ε.

[anon_cow1111]

Might be unrelated in this example, but when a message is written in a lazy ROT13-like cypher, the letter e becomes a notorious rat that allows anyone to break the entire thing in very little time.

Randomizing/obfuscating the letter case might buy you a little time, though I think it's something else entirely here.

[justsomehnguy]

Zvtug oR haeRyngRq va guvf RknzcyR, ohg juRa n zRffntR vf jevggRa va n ynml EBG13-yvxR plcuRe, guR yRggRe R oRpbzRf n abgbevbhf eng gung nyybjf nalbaR gb oeRnx guR RagveR guvat va iRel yvggyR gvzR.

Enaqbzvmvat/boshfpngvat guR yRggRe pnfR zvtug ohl lbh n yvggyR gvzR, gubhtu V guvax vg'f fbzRguvat RyfR RagveRyl uReR.

[ants_everywhere]

I had the same question about the upper case E.

Some of the E's look a little curly like epsilons but I'm guessing that may be an optical illusion.

But check out the 3 in "chancE3"

[Avshalom]

Legibility would be my guess. Can't confuse ᴇ for c.

[pbhjpbhj]

If we're guessing I have ideas:

1) it's just the typeface,

2) the teletype machine has unique letter so the machine it was received in is known (and hence which staff received it), reducing the ability to forge messages. Different machines could have had special letters, or all machines handling secrets had that particular "e"??

3) the machine broke and the repair shop only had a small-caps "E" handy.