When translating the Book of Mormon, how did Joseph Smith immediately pick up translation where he left off?

Although Joseph Smith translated the Book of Mormon in a short period of time, the translation period would have been full of interruptions. One unexpected part of translation was Joseph Smith’s ability to begin dictating without needing to be familiarized with where he previously left off. We would expect an author creating content on the fly to need to reorient themselves before continuing dictation, especially at the start of a new day.

Emma Smith (who said the Book was of divine authenticity “I have not the slightest doubt of it”). described the process as follows:

After meals, or after interruptions, [Joseph] would at once begin where he had left off, without either seeing the manuscript or having any portion of it read to him. This was a usual thing for him to do.
– Joseph Smith III, “Last Testimony of Sister Emma,” The Saints’ Herald, 1 October 1879, 290.

Emma mentioned this on at least two separate occasions and is not contradicted by any of the other witness statements.

How did Joseph manage to do this? Why would Emma feel the need to describe this aspect of translation if it wasn’t true?

See:

Evidence Central – Book of Mormon Evidence: No Translation Prompts

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