I ran The Gardens of Ynn over the weekend. I had been wanting to run it for a while: the decayed garden setting is beautiful and weird and different from the usual fantasy fare. It has a false tooth that grants d8 fire breath!
I ran it for 5e players. They had never played Old School Essentials / B/X before, but they are are mature and reasonable people who engaged with exploration, so mechanics were not necessary much. The adventure itself provides an events table, treasure, and encounters, and it was fun for everyone to roll for these tables.
Everything ran smoothly, for the most part, but one thing stood out to me: my players repeatedly asked me, "may I roll a check?" This is a habit 5e drills into you, so it did not come as a big surprise. I did not go to great pains to emphasize that OSE does not rely much on checks, and I encouraged direct problem-solving by describing what their character did, not abstracting the whole action behind a roll, so my players were not aware they were doing things "nonstandard" for an OSR game.
But the thing is, my players *wanted* to make checks. It is how they think about interacting with the world in a game, and an important way to fill in the fiction themselves. Granted, this locates the decision point for the game outcomes at a random dice roll, not the actions of the character. In many situations where 5e employs a roll, a careful description "should" accomplish the same thing (according to me). This is in contrast with the OSR principle of engaging with the world, and mechanics being a secondary emphasis.
Abstracting outcomes behind dice rolls does not invalidate the feedback loop of ability and skill checks in games like 5e. It is part of the fun. Emmy Allen, the author of Gardens of Ynn, has an interesting take on skill checks: they give the players agency by providing a mechanic where "you definitely get what you want". In the next tweet, she also mentions Dungeon Crawl Classics, describing its reliance on dice as the "Jesus take the wheel" approach.
In my games, I like this reliance on dice to provide direction for play. Rolls of the dice can provide interesting outcomes. And rolling dice comes with a little dopamine thrill, something else I like to provide. You might argue that OSE is simply a different type of game, one without many ability checks, but that dodges the issue. Checks can function as a mini game, and I am curious to understand how you could hack OSE to simulate the 5e ability check probabilities within OSE.
It turns out not to be hard very hard. Without getting into too many technical details, let me summarize by saying that ability checks and their difficulty are roughly equivalent in OSE and 5e, but in OSE high ability scores are more powerful than in 5e. This means that adjusting task difficulty relies much more heavily on the individual situation in OSE: a check roll modifier should be different when a character would or would not have skill equivalent to 5e proficiency, or even whether the character has a very high ability score.
OSE ability checks are essentially equivalent to a DC 11 check in 5e: an average ability score (10) has a 50-50 chance of success in both systems. Roll modifiers in OSE allow us to change the difficulty of a check to match the DC in 5e. But this is where things get complicated.
We have to think about the meaning of "difficulty." To make a long story short, to make a task more difficult for Superman, a bigger OSE modifier is necessary than for the average Joe. For average Joe (ability score 10), a +4 modifier is equivalent to DC 15, but +8 is needed to make the difficulty the same for Superman (score 18).
In this sense, high-powered OSE characters have even higher power than in 5e. On the other hand, low-powered characters have even lower power in OSE, as well. It may be surprising that OSE has more "power" than 5e. But, it fits into the OSR mindset of gritty characters at the extremes of existence: wins are big, but so are losses.
5e also has two major features that increase the power of its ability checks: (1) Ability Score Increases / proficiency leveling, and (2) skills and proficiency. The fact that ability scores and proficiency modifiers increase with level is hugely powerful, and gives greater weight to level increases. At an OSE table, proficiency can be corrected for by reducing the OSE modifier by 2 (for the average Joe).
So, it is possible to incorporate check-heavy play into OSE without modification of the base rules at all: the "calibration" comes from the size of modifiers. In summary, the practical considerations: modifiers in OSE can be adjusted 1-for-1 with with 5e, when considering the average Joe. For higher or lower ability score values, a bigger modifier is needed. And, when proficiency comes into play, the modifier should be reduced by 2.
Will I start using this at my table? I think so, with a default modifier of +4. This sets the bar for a check reasonably high: equivalent to a DC 15 check for average Joe. That seems justified: something truly left up to the fates, a situation where the player can really only rely on hope to succeed. Isn't that what OSR is about?
