The rule, not the exception

Does Pathfinder work on Obstacles?

This is a question that crops up every now and again in Kings of War, and the answer is no. Let’s have a look at the rule itself:

The unit suffers no movement penalties for difficult terrain, simply treating it as open terrain.
Pathfinder units are not Hindered for charging through difficult terrain.

So the quick answer to the question is no, the rule doesn’t say it does work on Obstacles, therefore it doesn’t.

It is, however, a nice entryway into a discussion on how we write rules in Kings of War.

The first thing to note is that we use very precise wording when writing rules. Difficult Terrain is a defined term in Kings of War and that term doesn’t include any other types of terrain, including Hills or Obstacles. When we refer to Difficult Terrain, we do not mean Obstacles and when we refer to Obstacles we don’t include Difficult Terrain. The thing to remember when it comes to rules for Kings of War is not to read more into the rules than we actually say. We didn’t forget to write Obstacles down, we specifically didn’t write them down. 

To help make that stand out, we’ve started Capitalising In-Game Terms to make it clearer that we are referring to the actual in-game definition, rather than just fluffily referring to some terrain that might be difficult (if that makes sense). Unfortunately this isn’t in the core rulebook, but you can see it in the Clash of Kings book and all others written by the Rules Committee going forwards.

When writing a game rule, generally you will list the stuff that it applies to or the stuff that it doesn’t apply to. We rarely do both. We could have worded Pathfinder as such:

The unit suffers no movement penalties for difficult terrain, simply treating it as open terrain, but does suffer it for Obstacles.
Pathfinder units are not Hindered for charging through difficult terrain but are still Hindered for obstacles.

Now, it’s wordier. Apply this to every rule in the rulebook where we specify both what the rule does apply to and what it doesn’t apply to. Surge not only has to specify that it can only be used on Shambling units, but also that it can’t be used on non-Shambling units. Charging specifies that it can only target enemy units and can’t target friendly units.

Add in all the exceptions and rules, and suddenly the rulebook has doubled in length. We keep things as short and concise as possible so that the rules are as short and concise as possible.

New Rules

The big issue that specifying both the rule and the exceptions is when you are writing new rules. Let’s continue with the discussion on Pathfinder. Let’s say that the RC create a new class of terrain, say Dangerous Terrain, which deals damage to any unit that crosses it.

At the moment Pathfinder states everything that it applies to (Difficult Terrain only) and anything that isn’t on that list will, by default, be the exception. So we can happily add new classes of terrain, safe in the knowledge that they will fall into the category of “things that Pathfinder doesn’t apply to”.

Imagine that we had specified the list of things that Pathfinder does apply to (Difficult Terrain) as well as listing the things that it doesn’t apply to (Obstacles). We add this new class of Dangerous Terrain and now we have an issue. It isn’t in either list, and there isn’t a default category for it to fall into.

We can list it in the rules for Dangerous Terrain whether Pathfinder does or doesn’t apply, but that increases the length of the Dangerous Terrain rules. It also splits the actual rules up. At the moment, the rules for Pathfinder are all in one place – under the Pathfinder rules in the rulebook. With Dangerous Terrain, players would now have to remember that the rules are not just in the rulebook, but also in whichever expansion introduces Dangerous Terrain.

There’s also the danger that we miss a rule when writing Dangerous Terrain. Ok, we remember that we have to include Pathfinder, but maybe we forget about Fly. Fly treats Difficult Terrain as Blocking terrain while moving At The Double, therefore do we need to make a ruling on that as well? There could be other rules that I can’t remember right now. If we forget about one of those rules then we have to issue errata to correct the mistake when the community inevitably discovers it.

We write the rules, or the exceptions, but not both

We find that a lot of the time when people has misunderstandings or questions about the rules, it’s because they’re reading more into the rules than is actually written. The rules are specifically written to only list either the rules or the exceptions. If we write both then it can nearly double the length of the rules and it causes conflicts for future expansions. If we use a term, and we will be capitalising all in-game terms going forwards, then we refer specifically to that in-game term. We didn’t forget one! (or if we did forget one then we will errata it)


  1. A nice write up.

    A suggestion for future supplements/edition could be to highlight keywords with italic or similar?

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