The half circle at the L side top of the 340 ?

I think it is a  road map of sorts to where his bomb of the bomb cipher is placed
it is on a road shaped like that and the dot symbol is the place on the road where it may have been placed .

Have you seen zodiackillerenigma.com yet? The guy uses the 340 as a grid to read the Phillips 66 map. It's really interesting and is probably right!

Yes ive seen it ...eh

I 'enigma' site is something I think has a few holes in it but overall it does seem interesting. The 340 being a grid instead of a cipher could explain why it was never solved.

Yes but what is the significance of the half circle?

I couldn't tell ya. I wish I were more into the ciphers. It's not that I have no interest, I just don't know much about them. The half circle is one of the stranger symbols though. But the one thing I like about the zodiackillerenigma.com site is that everything lines up perfectly with on the map and it all connects to one thing... golf courses. If the theory is true, then there is no message in the 340 and the only purpose of the cipher is to serve as a grid. Well, and to keep people busy trying to figure out something where there is nothing to figure out. I love the theory and if it's correct, whoever came up with it is a genius!!

Sorry, didn't mean to get off topic. I plan on studying up on different ciphers and see if I can come up with anything of my own, or add anything productive to anyone elses work.

Have you seen the zodiac ciphers. Article from Researchgate in SF ?
I looked once at library but it wont download right on android

Researchgate???

Its a think tank of sorts , SFCA  (dust off your Phd degree ) they have a article on the 340

I will try to link   ResearchGate.net  
It is just a summation of their /one of thems findings on the algorythem  results


https://www.researchgate.net/publication/220615769_Robust_Dictionary_Attack_of_Short_Simple_Substitution_Ciphers

Interesting.