While game rules are sufficient for legal play, they are not sufficient for good play. The long title Hoyle's Whist treatise promise "some rules, whereby a beginner may, with due attention to them, attain to the playing it well." In my vocabulary, these are not rules, but strategy. Consider the first of Hoyle's "general rules to be observed by beginners":
When you lead, begin with the best suit in your hand; if you have a sequence of king, queen and knave, or queen, knave and ten, they are sure leads...(page 11)While you are allowed to play any of the thirteen cards in your hand, Hoyle offers advice about which is the most likely to be successful.
Cotton offers no strategic advice in The Compleat Gamester; nor does Seymour in The Court Gamester despite his thorough description of rules. This, I believe, is Hoyle's major breakthrough--I know of no earlier strategic writing about cards games (although examples exist for chess and trictrac).
Partnership games such as whist or bridge pose an additional strategic complexity--good play requires partners to make agreements (and disclose them to the opponents) so the partners can communicate about their hands (based on the card played and not by other means; see cheating, below). Hoyle's first rule continues, "...begin with the highest of the sequence, unless ..." So Hoyle is suggesting leading the K from KQJx. The trick-taking power of each of the honors is the same, but Hoyle is implicitly saying that the lead of the K denies the A and promises the Q. This is a matter of partnership agreement and partners may choose different agreements (as some do in bridge when they play Rusinow leads).
In retrospect, Hoyle did a big disservice to gaming literature by failing to distinguish between strategy and partnership agreement. He really didn't have a chance of getting it right--it took almost 150 years to get the two concepts disentangled. Unfortunately, the failure to distinguish between strategy and partnership agreement persists in beginning bridge books to this day. Even worse some beginning books fail to distinguish among rules, strategy, and partnership agreements; some beginners think they are breaking the rules of bridge if they open with less than 13 points!
I said that remedies applied only to inadvertent irregularities. Intentional breaches of rules are cheating and are not covered by the laws. As Cavendish put it "There is a popular belief that card-laws are intended to prevent cheating. This belief, however, is altogether erroneous. the penalty for cheating is exclusion from society." (Clay's Decisions, and Card-Table Talk, p117)
Hoyle never discussed cheating or the means of detecting in, a theme that was common in Cotton's The Compleat Gamester and The Annals of Gaming.
There are certainly other categories I have not considered here. A common theme of early literature about games is the morality of gaming, surely another topic. One of the things I like about the Hargrave bibliography which I criticized here, is it classification of the literature (though she frequently put books in the wrong category).
I wrote this essay to highlight the role of Hoyle and I do think my list of categories helps us appreciate his contributions. Cotton's earlier writing was primarily existential with a good dose of cheating. Seymour set down rules and remedies for two card games and is, I think, under-appreciated for his contributions. Hoyle assumed knowledge of rules and dealt with remedies; he was the first to do so for whist. While I do wish he had distinguished partnership agreements from strategy, Hoyle was the first to discuss strategy for any card game. All-in-all, I think his reputation as the father of whist is well deserved.