Widdershins Wanderings

Cairn Crash Course

Image of the cover of Cairn with the hand flipping the bird circled in red

Lesson #1: The cover is flipping you off.

Introduction

Hello there. There has been a lot of new blood injected into the OSR/NSR space recently. I'll leave the hot takes as to why to Twitter, but a direct result of this infusion is that I have seen a lot of questions revolving around the OSR/NSR in general and Cairn in particular. Thus, in this particular post I shall endeavor to explain some of the particulars of the OSR playstyle for those completely new to this part of the hobby, but mostly I'm going to focus on Cairn and the questions that frequently come up over on the Cairn Discord.

So who should read this blog post? I mean, in general anyone who loves my writings (hi, Mom!), but in particular the following groups of people:

We'll start with a (really basic) overview of some mechanics and principles of OSR play. You can skip this upcoming section if you've ever read or played a version of B/X D&D or a retro-clone. I'm mostly writing this part for the people coming to us from the 5e or story-game space that have never dipped their toes into the OSR blogosphere or rulesets.

OSR Basics

OSR Logo in blue and white

OSR stands for Old School Revival or Old School Renaissance, depending on who you ask. There's a lot of argument over what the OSR is, how old its principles actually are, whether it is dead, etc. Regardless of its origins or exact definition, it is a very different playstyle compared to anything that people who started with 3rd edition D&D (me) or later are likely to have developed on their own. This is my attempt to briefly explain some of the core conceits and mechanics of the playstyle that often seem to trip people up. It is not an exhaustive list by any means, and any attempt to make it so would just be rewriting an existing OSR primer.

Conceit #1: Characters Earn Originality

In a lot of more traditional roleplaying games, you spend a lot of time creating an original character concept, writing up backstories of varying lengths, and using elaborate character creation systems that are designed to facilitate this originality by providing opportunities for customization. A character in an OSR game can typically be generated in a few dice rolls and some scrawled notes on an index card. This is important because the world doesn't care about your character in an OSR game. Bad decisions, or bad luck, can kill your character and derail any attempts to weave elaborate backstories into the narrative. This tends to mean that characters that do develop originality do so by surviving and being successful, earning originality as they make their mark on the world through their in-game actions.

Conceit #2: Discovery Through Interaction, Not Dice.

In more traditional games, it is typical for players to roll to determine if they spot traps, a secret door, or an enemy waiting in ambush. This is frowned upon in many OSR games, because secrecy and discovery are some of the main driving forces of the playstyle. As a result, you are expected to investigate places and objects via describing your character's actions, using critical thinking and common sense to uncover things and avoid hazards. For some games with a different focus this would be considered a waste of time, but sometimes a lack of mechanical focus tells you what a game or playstyle wants to spend time on.

Conceit #3: No Social Skills/Checks

Similar to the preceding point, characters are generally expected to talk to anything they come across, not roll a skill check to see how the social interaction went. This doesn't mean that everyone is talking in-character in funny voices at every OSR table (although sometimes this is true). In general the idea is to make players figure out the general premise of what their characters want to say and how they want to say it. This rewards player investigation into the people, places, and things of the world they are playing in. It also helps every player to feel like they can contribute to a conversation, not just the ones that have the attributes and skills for it.

Conceit #4: Game Master Neutrality

Those who run the game for the rest of the players are expected to act as neutral arbiters rather than be "fans of the characters" or "help facilitate great stories". This is difficult for many people to do, so there are various mechanics (see below) in many OSR games that are meant to help facilitate this neutrality. I don't really think true neutrality is possible, for the record, but using mechanics to determine things like how Monsters initially feel about you or when they flee battle go a long way towards achieving it.

Conceit #5 Combat Should be Avoided or Fought Unfairly

A frequent statement that gets touted as a truism in OSR circles is "Combat is a fail state". This is not necessarily true, but it is true that if you can avoid a fight and get the thing you want, you should do that. Generally speaking, combat should only be fought when it seems like the only (or only reasonably expedient) way of getting something you want or need.

Even then, combat should be fought as unfairly as possible. Ambush, use fire-bombs, separate foes using false pretenses, etc. In many newer forms of D&D, combat can often seem to be the point of the game. In an OSR game, combat is just one of many methods of overcoming obstacles in the way of character success.

Mechanic #1: Roll-Under Attribute Check

Any time a game or adventure tells you to do a roll-under check, it is telling you to roll a d20 and try to get under (or exactly on) the number the attribute it is tied to. For instance, if a module says that PCs should roll a Strength check, a character with a Strength of 14 would be expected to roll a d20 and try and get a 14 or below. This may seem odd to people used to rolling high and adding modifiers, but it has the benefit of requiring no math and an instant understanding of the results of a roll (you don't have to pause and add or subtract modifiers). There are variations, such as counting a roll of exactly the attribute's number a failure or using xd6 instead of a d20 to modify difficulty, but the basic concept remains the same.

Mechanic #2: X-in-6 Chance

Another mechanic that is used frequently in adventures due to its prevalence in B/X D&D and the like. It is a way of letting a dice roll determine something that you don't want to leave purely to Game Master discretion. Essentially, whatever X is determines your chance of success. You would roll a d6 and if it lands within the range described you get a favorable outcome. A 3-in-6 chance, for instance, is essentially a coin flip. Whereas, a 1-in-6 would be very low odds of success and a 5-in-6 very high. I prefer it to have parity with roll-under and consider low results successful, but other people prefer to look at higher rolls more favorably (Cairn's Die of Fate is an example of this). It doesn't really matter as the statistical chance is the same.

In general, this is a great way to try and decide something that would benefit or harm the PCs without violating neutrality. Though, personally, I tend to like 3-in-6 chances like the Die of Fate for such situations because it gives both possibilities even odds.

Mechanic #3: Reaction Rolls

I said before that social interactions are never bypassed or sped through via rolling, but a GM typically determines someone's starting disposition by doing a Reaction roll, which is done by rolling 2d6 and comparing the results to a chart. Typically extreme results are less likely both because the most extreme positive and negative Reactions are typically assigned to a single number (12 and 2, respectively) and also because the use of two die will skew the average result towards the middle.

Reaction rolls are really important if you want to show PCs that they don't have to constantly fight anything and everything they encounter. This is important, because parties that fight everything that moves will quickly get in over their head and die horrific deaths.

Mechanic #4: Morale Checks

Another tool in the "maintaining neutrality" toolkit. NPCs roll these when certain conditions are met. Usually when enough NPCs on their side are defeated, they personally are under threat of death, or a situation created by the PCs is frightening enough to warrant checking to see if they should turn and run. It is typically rolled with 2d6 (though I have seen 1d12) and the result is compared to the NPC's Morale score. The higher the Morale, the less likely that NPC will flee.

This is a useful mechanic for both saving time (playing out the clean-up part of a battle is pretty boring), fairly deciding enemy behavior, and (perhaps most important of all) modeling the idea of running away being a viable option for PCs.

Cairn Frequently Asked Questions and Misconceptions

For Use With Cairn These are the things that come up a lot on the Cairn Discord, Reddit, etc. This list is obviously not definitive either, but if I have to answer it enough on the Cairn Discord it will likely be added.

What is HP?

HP is short for Hit Protection. It's all of the vigor, skill, and luck that a PC or NPC possesses that allows them to avoid damage. If a PC still has HP, they have not been hit in a way that would cause them lasting harm. This is a really important thing to keep in mind when describing Combat for aesthetic reasons, but also because it helps you adjudicate things on the fly like poisons, draining touch attacks, and being mauled by a Grizzly Bear.

A common mistake I see with HP is when adjudicating traps. Traps typically target attributes directly, often Strength. Fictionally this makes sense, but mechanically there is a very good reason for this as well: HP is easily recovered in Cairn, and so many traps would be trivialized as a result.

The How and Why of Critical Damage

Critical Damage happens when a PC or NPC runs out of HP and the damage gets into their Strength. The important thing to remember here is that when STR damage occurs it means that a solid hit has taken place, but it doesn't mean that hit is a mortal wound. In order to determine that, a Critical Damage save is made using a PC or NPC's reduced Strength score.

A character that passes this save has been weakened, but manages to avoid a critical injury. They are the character that, though stabbed, forces their attacker away before any serious damage to their vitals occurs. They are the PC that dislodges the snake before deadly venom can be pumped into their veins.

A failure on a Critical Damage save means that the PC or NPC's strength has failed them. They are incapacitated at best, and potentially face more deadly or lasting consequences depending on the nature of the threat they are facing.

Armor: Mechanical and Fictional Benefits

The first thing to understand about Armor is that you can never go above 3 Armor. This is important, as even an impaired attack has the potential to do damage, but higher Armor would render this impossible. If you are designing an NPC and you feel like they should have more than 3 Armor, they should probably just be immune to normal attacks (and this immunity should be clearly telegraphed to players).

While there is no mechanical distinction between many of the various sources of Armor by default, Fictionally it matters a great deal what a PC is using. Chainmail and shield is functionally the same as Plate, but if you fall into a body of water you will be thankful if you have the former and dead if you are wearing the latter. Shields can be wedged into trap mechanisms (or the maws of monsters), while helmets can help protect your head from falling debris.

Scars

Scars occur when a PC (not NPC) is reduced to exactly 0 HP, but does not suffer any Strength damage from the attack. If Armor prevents an attack from reducing a PC to 0 HP, a Scar is not inflicted. If even a single point of STR damage is inflicted, a Scar does not occur.

A PC gets the Scar that corresponds to the amount of damage dealt to them that brought them to 0 HP (Armor reduces this amount). Thus, a PC with 2 Armor with 5 HP that was hit with a 7 damage attack would take Scar #5.

NPCs and Exceptions

NPCs follow most of the same rules as PCs, with a few exceptions:

Saves, Not Checks

There are no such things as Ability Checks or Skill Checks in Cairn. In Cairn, your goal is generally to overcome obstacles through Teamwork, Planning, Caution, and critical thinking (notice that the capitalized terms are Player Principles). This blog post is useful when determining whether a situation calls for a Save or not.

If there is nothing at risk, there is no reason to Save. This is a hard habit to break for those who are used to calling for more traditional Checks in situations where you are uncertain of the outcome but there is nothing really at risk. If a situation is not risky, simply assign a cost in time or resources that seems reasonable (or just let them do it for things that are trivial enough).

If the player in question isn't satisfied with the cost as assigned in such situations, they can always put themselves in a risky situation in order to potentially change the cost to be more in their favor. A good blog to read on this subject would be Dilemmas: Pick or Push by Chris McDowall.

What About Difficulty?

When a Save is made, you have the same odds regardless of the size of the risk you are taking. When grappling with this realization, many people instinctively reach for Advantage and Disadvantage as a way to fix this "problem".

Instead of doing that, it is more helpful to instead ask yourself "What exactly is at risk if the Save results in a failure?". Just as not all risks are the same, the consequence of failure should not be either. For a more in-depth explanation of this approach, please read Difficulty in Bastionland by Chris McDowall and Advantage and Impact by Dreaming Dragonslayer.

Opposed Saves

In Cairn, there is never a situation where there is a "roll-off" to see who wins in a situation where two sides are opposed. In such situations, the side that is most at risk is the one that must make the Save.

Combat: The Multiple Attackers Rule and Simultaneous Resolution

In Cairn, when multiple PCs (or NPCs) attack the same foe, all damage dice are rolled together and the highest result is the one kept. This has the effect of encouraging PCs (and NPCs) to target different opponents rather than dogpiling on one enemy combatant at a time. If ignored, both NPCs and PCs would be defeated at a much more rapid pace.

A key thing to understand with this rule is that PC actions are declared separately and rolled simultaneously. This means that if there are four PCs who are taking actions in Combat, they each must declare what they are doing (PCs 1 and 2 are attacking the Troll, while PCs 3 and 4 are attacking the Bugbear) and only then are dice rolled and the Round resolved. This means that PCs must decide how much of their offensive they want to invest in a single foe. You can't simply have the PC with the best weapon attack an NPC, and only have other PCs step in if they get a bad roll.

Of course, this does mean that in a situation where the PCs greatly outnumber NPC combatants it will often not make sense for everyone to attack. This is by design, as it encourages PCs to think of actions to take outside of the paradigm of Combat.

Spell Casting Times, Durations, and Saves

Generally speaking, anyone can cast a spell given a Spellbook and sufficient time. The more time a PC has, the better the results of the spell should be (this is called enhancing). If a PC doesn't have sufficient time or safety to cast a spell, a WIL save is appropriate.

How much time is appropriate varies by the Warden. Spells are not generally possible in Combat without sufficient precautions being taken (a defensible position, multiple armed PCs between the PC with the Spellbook-using PC and enemy combatants, etc.). How many Rounds of Combat it takes is subject to Warden discretion based on the nature of the Spellbook being used (with the option to speed up the casting upon a successful WIL save).

Relics and Scrolls typically are treated as easier to use than Spellbooks, and can be used in Combat without penalty.

There is no specific rule regarding spell duration. Generally, the nature of the spell should be used by the Warden to determine such things. A good rule of thumb is that a spell should last for at least one Turn (10 minutes or so), and that a PC can attempt a WIL save to extend the duration (with appropriate consequences upon a failure). Some spells, however, might lend themselves to a duration of a day (or even be permanent!) depending on the nature of the spell in question.

Due to the difficulty of using Spellbooks, especially in risky situations, Saves are not generally called for when an NPC is impacted by a spell. It just works.

Addendum: Starting Adventure Recommendations

Beyond rules questions, the single most commonly asked question on the Cairn Discord has to do with best adventures to use with Cairn if you are new to the system and/or introducing new players to the game. I will likely be updating this list as time goes on with more modules and the rationales for each, but here is an initial list to get you started.

Best One-Shot Modules

Best Multiple Session Modules

#cairn