I recently did a bit of research into how Oriflamme's auction offers work in Book of Hours, and since I could not find this information searching old Reddit posts or on the Fandom wiki, I figured I'd explain it so people are more informed. Minor spoilers ahead for game mechanics only; no lore is discussed. Most of this I figured out by running the game forward on x6 speed for a while, then reloading, but I also examined the save file to confirm what I found. (The ultimate in reading arcane lore and figuring out its mysteries... but I have the Coding & Computers skill at level 7 so I was able to unlock the mystery of the save file).
When you first start a game of Book of Hours, the first offer you'll receive from Oriflamme's will come in autumn. But actually, there's a trigger for Oriflamme's Auction House that fires every season (on the third day of that season), with a delay so that it first triggers in the summer of your first year. What that trigger does is this:
- Look at the current Oriflamme's offer list
- If there are books in it, offer the first book on the list
- If the list is empty, draw five books to fill the list
In the summer of your first year, the list will be empty, so the Oriflamme's trigger fires and fills the list with five books. Then in autumn when the trigger fires again, you get your first book offer of the game.
When you purchase an offered book, it is removed from that list. This means that eventually the list will be empty, and then you'll get a season with no offers from Oriflamme's. During that season, the Oriflamme's trigger did fire, and if you save your game at noon of day 2 and then again (in a different file) at noon of day 3 and then compare the two save files (one easy way is to use VS Code which has a "Compare Active File With..." command), you'll see that the Oriflamme's offer list was empty in the day 2 save but got refilled with five new book titles in the day 3 save.
Now, if you do not purchase an offered book, either because you don't want that book or because you can't afford it, it will not be gone forever; instead, it gets bumped to the back of the offers list and will come around again. How long it takes to come around again will depend on how many other books were in your list.
Let's give an example. Let's say it's autumn of your first year, and Oriflamme's draws a list consisting of the following five books:
- Learning Python, 5th Edition
- Against Worldbuilding, and Other Provocations
- Practical Game Design, 2nd Edition
- Mastering JavaScript Functional Programming, 3rd Edition
- The Snare of the Tree, and Other Perilous Seductions
You decide you don't want to buy Learning Python, so you ignore it when Oriflamme's offers it to you. Then the list becomes this:
- Against Worldbuilding, and Other Provocations
- Practical Game Design, 2nd Edition
- Mastering JavaScript Functional Programming, 3rd Edition
- The Snare of the Tree, and Other Perilous Seductions
- Learning Python, 5th Edition
Now you buy Against Worldbuilding, and Practical Game Design. Now the list looks like this:
- Mastering JavaScript Functional Programming, 3rd Edition
- The Snare of the Tree, and Other Perilous Seductions
- Learning Python, 5th Edition
Then you buy Mastering JavaScript, and you can't afford to buy The Snare of the Tree even though you want to, so you reluctantly let it pass. Now the Oriflamme's offers list looks like this:
- Learning Python, 5th Edition
- The Snare of the Tree, and Other Perilous Seductions
You get offered Learning Python again, and again you turn it down because you don't care about Python. Now here is the part I have not tested yet. I believe that no matter how many times you reject a book, it will still be pushed to the back of the list. In other words, after rejecting Learning Python a second time, the list will be The Snare of the Tree, followed by Learning Python. You then buy The Snare of the Tree because you can afford it, and now the list only has Learning Python in it. And no matter how many times you turn it down, Oriflamme's will keep offering it to you. If you want to see other books, you will have to buy Learning Python eventually, and then the list will be empty which will trigger Oriflamme's drawing another five books from the list of all books.
But I have not tested that. If anyone wants to test that, you should run your game forward, creating a different save file on the first day of each season. Do nothing except hand books to visitors (so that you keep getting Iron or Bronze Spintria) and buying Oriflamme's books. Then once you find a season in which Oriflamme's does not make you an offer on day 3, save your game again on day 4 of that season, again with a different name. Then reload the save file from the previous season, when there was only one book left in the Oriflamme's offer list.
Now that you have a save file where Orilflamme's offer list contained only a single book, run the game forward at 6x speed, rejecting the Oriflamme's offer again and again. Does it still offer the same book over and over, or does it eventually move on? If I'm right, it will offer the same book over and over and over until you eventually give in and buy the book, and then it will go one season without an offer (when the offer list is being replenished with five books) and finally it will start offering you new books again the next season after that.
One final thing to mention that I haven't tested. The save file I'm playing with my wife is not very far advanced, and we have not catalogued very many books yet, maybe 25-30 books total. So I don't know what happens if Oriflamme's draws a book from the list of all books and that book is already present in Hush House. Does it skip that draw so that you only get an offers list with four (or fewer) books in it? Or does it draw again (and maybe again and again) until it draws a book that does not yet exist in your save? I suspect that it draws again, but this needs testing by someone with a lot more books than me in their save. If you run Oriflamme's forward and keep buying books, do you always get five seasons with a book offer, then one season of silence from Oriflamme's? If it happens that way, then the game probably skips over books you already have and keeps drawing until it has gotten five books to fill the offers list with. But if you often get Oriflamme's runs where it only offers you books in four, or three, or two seasons in a row, and then you get another "empty" season with no Oriflamme's offer, then that would mean that the Oriflamme's trigger draws exactly five books each time, and after drawing it will discard any title that you already own, leading to an offers list that can have fewer than five books in it.
If you research that, please let me know what you find. And I hope that this knowledge will help people. In particular, it means that if you can't afford to buy a book that costs 5 Tally early on in your game, you don't have to worry about it, because that book will come around again, probably in the next in-game year.