Arkand is in Khul, according to the outline of The Keeper of the Seven Keys, but no further details are given of where it actually is. There are a number of areas in Khul which haven't been described in detail and which are large enough to contain the city of Arkand and the other places named in the outline of The Keeper of the Seven Keys. A number of things in this description may help us to place Arkand more precisely:
- The book description mentions not only Arkand but also places called Fernor, Sariandor, Kelados and the Tower of Doom. That's a reasonable number of new places and although they need not all be in the same area, they might well be.
- There are two mentions of people from Hachiman in the book description - Uldarik Hsao and Fudoshin Raiko. We also have a character called Prince Chemcho of Sariandor. Although Sariandor doesn't sound very "Eastern", Chemcho does. No other places in Khul are named. This might suggest that Arkand is near Hachiman.
- There is mention of a paladin Order of Knights Errant, which seems more "European" than "Eastern".
None of this is definitive, but one area of Khul is reasonably well suited to this assemblage of facts - the area of eastern Khul north of Hachiman and south of the Gulf of Ariona. This would certainly give us a Hachiman link, and there's plenty of room in this area for all of the places mentioned. One other possibility is southern Khul, between Hyennish and the Inland Sea, but there is much less room here for new locations, and it looks like this area may rather be a little populated desert or steppe area.