Chess pie is closely related to Vinegar Pie, and the two terms are often used interchangeably. Vinegar pie generally adds somewhere between a teaspoon and tablespoon of vinegar to the above ingredients to "cut the sweetness". Actually, it makes very little difference in the taste.
The pie seems to have no relation to the game of chess, which has led to much speculation as to the origin of this term. Some theorize that the name of the pie traces back to its ancestral England, where the dessert perhaps evolved from a similar cheese tart, in which the archaic "cheese" was used to describe pies of the same consistency even without that particular ingredient present in the recipe. In North Carolina and Old Salem Cookery, Elizabeth Hedgecock Sparks argues that the name derives from Chester, England. One folk etymology suggests that it was referred to as "just pie", which soon shortened to "jus' pie" and then corrupted to "chess pie". There is also a theory that the word "chess" pie comes from the piece of furniture that were common in the early South called a pie chest or pie safe. Chess pie may have been called chest pie at first because it held up well in the pie chest.