A Cipher Thought Experiment

[nablator]

It's not an escape character, the whole cipher is multi-to-multi mapping, a few characters (usually 1 or 2) of the cipher correspond to 1 or 2 characters of the plaintext. With "/" the mapping is very simple, you replace any occurrence of "/X" with "x", except "/K" makes a "c".

My (better) understanding now is that the cipher is a polyalphabetic substitution of single letters of the plaintext (except "th") by 6 letters (K, O, P, R, S, T) with 6 alphabet selectors (/, 4, G, L, M, N) inserted in the ciphertext to signal a change of alphabet. The default alphabet selector (/) is omitted at the start of words.