Some readers may remember that I’ve got my own “fantasy heartbreaker” tabletop RPG system perpetually on the back burner, whimsically titled YAOSC (Yet Another Old-School Clone). The basic design elements for most action resolution are:

• Roll equal to or under your score to succeed. So if you have a score of 4 in a skill and roll a d6, then 1-4 are successes, while a 5 or 6 is a failure.
• Sliding dice scales. This means that a moderate task may ask you to roll a d6, while a simple task calls for a mere d4, but a steep challenge asks you to roll a d20. The same score of 4 can mean anything from guaranteed success to slim odds.

Yesterday I was thinking about what happens when a character picks up an informational book, such as Philliden’s Walking Knowledge, in mechanical terms. There’s a chance that they can learn something, of course. But how do you determine how easy it is to learn, and how do you decide how much knowledge can be extracted from a text (or similar source)?

My first thought was to automatically grant skill points in return for time invested. So, say you have a textbook and you spend a month reading through it, a little each day. Maybe you gain a skill point in its subject matter. Maybe a slim monograph or the Walking Knowledge can only ever give you one point in a subject, while a hefty tome or series can grant up to three +1 skill boosts.

The immediate problem with this one is the book-keeping. If a group gets their hands on an informational text, suddenly you have to keep track of how many skill points each character has gotten from it. It also doesn’t make sense for a low-level book to be able to increase the skills of an expert. Sure, even a master of the field might be able to glean new insights from an introductory text, or be reminded of tips that they’d forgotten, but would it be enough to justify the master getting the same +3 benefit from a book as a neophyte? I think not. There are a number of possible kludges that address this particular issue, but they all only make the book-keeping problem worse.

The solution I came up with is intuitive and pleasingly simple. Forget about each bit of instructional material (I’m mainly thinking of books, but it doesn’t have to be!) having a set bonus that gets doled out in increments over time. Instead, it has a die rating. A beginner text might have a rating of d4, while an advanced one might have a rating of d12. Every increment of study (a month of daily reading and practice, or whatever it ends up being) allows the player to roll the book’s rating die and check the results against their skill level.

Success on this role leads to the character’s skill being increased by one, up to a maximum of the die size. So a d4 book can increase your skill level to 4 and no further; a d12 book can increase your skill level to 12. But the more advanced texts are also more difficult to grapple with: a super-sophisticated treatise with a d20 rating may have the capacity to bring a reader up to expert level, but a greenhorn with a score of 1 only has a 5% chance per time increment to learn enough from the text to advance at all. Your book-keeping for a given text is limited to its difficulty rating, which through a single roll determines both how easy it is to gain information from, and how far it can take you.

I am aware that this is an oversimplification. It’s easy to imagine a poorly-written beginners’ survey text that requires a lot of work for little reward, or a beautifully written masterpiece that smoothly guides the reader from basic principles through to the most complex concepts. As a general shorthand, though, a single rating feels like it gives us a nice balance between simulation and streamlined gameplay.

The downside of this system is that it means, counterintuitively, that if you know nothing about a field (score of zero in a skill), then no amount of book-reading can ever teach you anything. Since this runs counter to reality as we know it, it might be worth ruling that relatively simple texts (anything with a d4 rating or below, perhaps?) is easy enough that a roll of 1 counts as success even if the character’s skill is zero.

The system could even be expanded to work with in-person teaching. The instructor could choose a die size (i.e. choose the difficulty and pacing of their lessons), and then both teacher and student roll using that die. Two successes means that the lesson is learned and the student gains a skill point. Two failures means that the teacher was lost in their own little world while the student flailed and learned nothing. One success and one failure should not grant any skill points, but might represent progress that makes later rolls slightly easier in some way.