One wonders here if the use of the simple noun north might not be a mistake for the adjective northern, as in Alma 22:29: “the Nephites had taken possession of all the northern parts of the land”. Another possibility might be northernmost, as in 3 Nephi 7:12: “that they should take their flight into the northernmost part of the land”. These three instances are the only examples of any cardinal direction occurring with the noun part(s); there are no examples of part(s) that are modi- fied by the morphemes east, south, or west. Moreover, there is only a single example for each type based on the morpheme north. This means that there is no strong evidence for emending the text here in Helaman 1:23. In fact, the King James Bible has cases of north parts and east parts:
Here in Helaman 1:23, the original manuscript is sufficiently extant that we can clearly read the entire word North just before the lacuna, about two thirds of the way across the line of 𝓞:
-rough with the sword that he might obtain the North (p ) ARTS OF THE LAND & SUPPOSE
The critical text will therefore maintain the reading in 𝓞, “that he might obtain the north parts of the land”.
Summary: Accept north parts in Helaman 1:23 even though northern parts seems more appropriate in current English; the original manuscript reads North, and there is evidence for this usage in the King James Bible.