Basically most AI/Lisp vendors also offered a Prolog in Lisp. As a Prolog implementation the standalone Prolog compilers were faster and had more Prolog feature

Basically most AI/Lisp vendors also offered a Prolog in Lisp. As a Prolog implementation the standalone Prolog compilers were faster and had more Prolog features, but since the Lisp tools were a bit more mature, even in Japan some projects used Prolog in Lisp. There was a lot of research for AI hardware in the 80s and also for Prolog hardware. I once saw a Japanese Prolog Machine (a special purpose workstation with a Prolog environment), but I didn't have the chance to actually use it. With faster/cheaper Intel or RISC processors and a lack of research funding, the topic of specialized hardware was mostly ending in the early 90s.