Those with a more than passing understand of computer hardware architecture or programming are probably familiar with the Protection Ring Model of hardware permissions. In this model, computer hardware (notable CPUs) have defined “modes” or “rings” that restrict direct access to certain resources. Traditionally, there are four rings (starting at 0 because computers), with ring 0 being the most privileged in terms of access, and ring 3 being the least. When writing code meant to operate in a given ring, if you need access to a resource from a lower ring you must do so through a function call. I.e. a program like Discord opening your web camera must ask the operating system to do so, it can not simply shunt voltage to the camera itself. It must call something like “OS_GET_CAMERA_FEED()” (if you’re lucky, it’s probably actually an unintelligible cstring") and then the operating system will handle the next steps (like sending a notification to the user that the camera is being accessed in an ideal world). Meanwhile a program written for ring 0 (a “kernel mode” program) CAN simply shunt the voltage over, without going through any OS protections for the camera.
Obviously, this is quite simplified, the details of how this system actually operates varies. Many modern systems don’t have all four rings for example, or prevent kernel code from being written except by specific people. Temple OS famously allows the USER to write at Ring 0. However the principle is the same: the lower ring you operate at, the more you can do but the less protections you have. While writing a program that causes a crash or other nasty side effects is possible at any ring, it is almost trivial at ring 0. Programmers who work here need to have specialized knowledge of not only programming, but the specific architecture they are programming on. Many of these devices have foot guns that can not only crash the computer, but render the hardware unusable forever. Things like this are less common in Ring 3. But simultaneously, you can simply DO less at Ring 3, as you are constrained by the system into using only safe access paths.
Game Mastery follows a similar model. There are many ways a Game Master interacts with whatever system they are running. These can track pretty neatly into Three Rings:
Ring 2: Using preexisting entities 1 and rules to run a game.
Ring 1: Creating New entities using in-system tools and adjudicating unclear situations at the table.
Ring 0: Creating new rules or entities without relying on in-system tools.
With these rings, the same general principle applies: the lower ring you operate at, the more you can do but the less protections you have. It is not impossible to ruin a session by picking a monster way out of tune with players current power level, but you are unlikely to blow up your whole campaign 2. Meanwhile, your neat new rule that gives all living beings an allergy to oxygen is going to cause the game to be unplayable. Thankfully, game systems are not like computers and it’s pretty easy to revert bad Ring 0 changes without lasting effect, except maybe some ribbing from your buddies.
Now, like with computers, the size and shape of these rings varies between systems. 5e was pretty notorious for having basically no guidance on creating custom monsters, races, or anything 3. To the point that there are entire wikis dedicated to hashing out home-brew in a way that works and is balanced. In a sense, 5e often forces Dungeon Masters to operate at Ring 0, when they would perhaps rather operate at Ring 1. Many get around this with simple reskins (These goblins are now mudmen! Don’t look too closely at the pencil marks over the abilities and stat line!). This re-frames a Ring 0 problem as a Ring 2 one. Instead of trying to create a new monster, just use an existing one and call it something else. Problem solved. Not everyone finds re-skins a compelling solution, but it does work. Just look at OPR and how many army rules do exactly the same thing, just with different flavorful names. This can also be applied to items and spells, and a whole host of things. But it does start to feel samey and it should, as you are literally using the same stuff.
ACKS II on the other hand, provides an extremely robust set of both Ring 2 and Ring 1 support for its Judges, and more importantly it calls out exactly where they will need to step into Ring 0 to add whatever they want to their game. A recent example from my current Shallow Sea campaign is a player wanting to know the cost to research a spell that recreated Bed of Iron from Pathfinder. Since ACKS provides a custom spell builder, it’s quite possible for me to take that request and generate a spell with the effect and provide an estimate on research cost. However when I opened the book, I could find no way to build the effect with what is in the spell builder. However, I could build a spell that bestows a Proficiency for a limited time. But, alas there is no proficiency that allows sleeping in armor. So I simply created one for my setting, added it to the appropriate lists and then built the spell and handed the player back a cost estimate.
In this example, I stepped through all three rings. Starting at Ring 2, the spell research system. These rules are player accessible (they are in the Revised Rule Book), and extremely well defined. I knew up front exactly how to adjudicate researching a spell of a given level, I just needed the spell level. Which lead me to Ring 1, the spell creation rules. These are in the Judge’s Journal for a reason, and they allow the creation of spells that are more or less in the game parameters 4. Finding that there was no spell that did exactly what I wanted, I had two options. Both which required into the murky depths of Ring 0: Either create an Esoteric spell (which are specifically tagged as being outside the spell creation rules) or add a new Proficiency (which does not have an easy to follow creation kit in the JJ). I chose the second option, but either way I knew I was entering into possible breakage territory. So naturally, I did what any good programmer would do and got my implementation checked by other, more knowledgeable people before getting back to my player. The ACKS discord is extremely helpful in this regard. In most other games, this example devolves into Ring 0 almost immediately. A player “creating a new spell” is very rarely an option, and when it is, there’s rarely guidance on how to do it well; and since a game master seeking to do this now has spend a lot of surface area making things up with little to no guardrails, there’s a much higher chance that something breaks. Either spell research becomes too easy, and now you’re playing Ars Magica, or the spell is really broken in some way, or doesn’t function at all the way you intended. The list goes on. By having a robust set of Ring 2 and Ring 1 tools, ACKS II helps me limit the amount of time and surface area I spend in Ring 0 just to keep my game ticking along.
In the end, this is the proficiency and spell that were created:
Weighted Resting This character may sleep with up to 5 st of encumbrance without incurring a non-restful sleep penalty. Any encumbrance above this is treated as normal (eg, a character with 6 ST of encumbrance still must make a throw of 6 or have non-restful sleep).
Amer’s Armored Respite (name pending) Level 2 Transmogrification - Touch - 12 hours Target Creature gains Weighted Resting proficiency for the duration.
What I particularly like about this, is that the spell is very clearly an ACKS-y spell. If I were running 5e or some flavor of B/X I would have likely just directly copied the effect of Bed of Iron with no thought to the consequences. Which, in this case there may not be any serious ones but you never know. Instead though, because I was provided with gated systems that allowed me to only use the parts of the POWER OF GAME MASTERY that I truly needed, I ended up with something unique and far more suited to the game.
This is not to say that I think operating in Ring 0 is wrong and should be avoided completely. But I do think a Game Master who is operating there should be aware that’s what he is doing, and be prepared for the consequences of it. I also appreciate when a game system goes out of it its way to help Game Masters of that system to be judicious about working in this mode. There may be more on this topic in the future, as I don’t believe I’ve quite aired out all my thoughts on it. But for now
Sail On!
ShockTohp
Footnotes:
1 Entities for this purpose includes monsters, characters, items, spells, ect.
2 If you are consistently doing this, it’s a skill issue. Not a problem with the Ring itself
3 This may have changed since Xanathar’s I don’t really know.
4 You absolutely can build broken spells. That’s why they are in the Judge’s Journal and require review before approval.
This is a good example, and a good translation of the framework. If you wanted to extend it to be a four-ring model to match computing, a good candidate would probably be Ring 3 as published modules, where you're not just using verified-safe building blocks, but running them in a scenario constrained for specific gameplay ends.