Yu-Gi-Oh! Duelist is part of the English Yu-Gi-Oh! manga. It occurs when the plot shifted to mainly Duel Monsters related storylines. While the Japanese manga continued numbering as normal and kept the name Yu-Gi-Oh!, Yu-Gi-Oh! Duelist started numbering volumes and chapters from 1.
The first chapter, Duel 1 is Duel 60 in the Japanese manga. Volume 1 of Duelist is Volume 8 of the Japanese manga. The plot contains the original script for the Duelist Kingdom and Battle City arcs.