WILLz → Ai in 1977
Source: details in The Enigma of July 1995 and npl-folk email from Ai.
First Issue: Jun 1977
The ai is, as everyone knows, the crossword puzzle sloth, and I've been a constructor for 45 years or so. AI also stands for artificial intelligence, which I teach about, and for Arthur Irwin, my given names. (I later found out that AI also stands for artificial insemination, but never mind!).