A common form of mapping for RPG cities is the block map. For example, here’s the city of Kintargo from the Hell’s Rebels adventure path:

A common mistake when looking at such a map is to interpret each individual outline as being a single building. For example, when I posted a behind-the-scenes peek at how I developed the map for the city of Anyoc years ago, a number of people told me I’d screwed up by leaving too much space between the buildings. Except the map didn’t actually depict any individual buildings: Each outline was a separate block, made up of several different buildings.

When people look at a block map and interpret it as depicting individual buildings, how far off is their vision of the city?

Well, we can actually see this exemplified in a few cases where artists have (in my opinion) misinterpreted block maps. Blades in the Dark, for example, has a block map for the city of Duskwall. Below you can see a sample of that block map (on the left) next to a block map of a section of Paris (on the right).

If it was not self-evident, the interpretation of the Duskwall map as a block map is supported by this description of the city from the rulebook:

The city is densely packed inside the ring of immense lightning towers that protect it from the murderous ghosts of the blighted deathlands beyond. Every square foot is covered in human construction of some kind — piled one atop another with looming towers, sprawling manors, and stacked row houses; dissected by canals and narrow twisting alleys; connected by a spiderweb of roads, bridges, and elevated walkways.

You can see that if you interpret Duskwall’s map as detailing individual buildings, the layout of the city actually becomes far more organized and well-regulated than seems intended by the text. This is, in fact, a common problem when GMs misinterpret block maps: Their vision of the city, and the resulting descriptions are heavily simplified.

For example, when Ryan Dunleavy decided to develop a large version of the Duskwall map, he interpreted each block on the map as being an individual building (or, occasionally, two). Compare the resulting illustration of a single block in Duskwall (on the left) to what a single block in Paris (on the right) actually looks like:

(Please don’t interpret this as some sort of massive indictment of the artist here. Ryan Dunleavy’s cartography is gorgeous, and I recommend backing his Patreon for more of it.)

You can see another example of this with Green Ronin’s Freeport. When first revealed to the world in 2000’s Death in Freeport module, the city was depicted using a rough block map:

In 2002, for the original City of Freeport, this was redone with most of the blocks being represented as individual buildings:

The map was redone again for The Pirate’s Guide to Freeport, this time reinterpreting the original outlines as a block map:

I pull out this example primarily to point out that sometimes a block map outline IS, in fact, a single building. Because some buildings are really big. Or, in other cases, they might represent walled estates, as shown here with the estates along the western edge of the map.

And here’s a real world example of this from Paris with both the Grand Palais and the Petit Palais:

(click for larger size)

The north-south cross section of the Grand Palais is fairly comparable to the Parisian block shown above.

CONCLUSION

My point with all this basically boils down to don’t mistake the map for the territory. One of the great advantages of the block map approach to city mapping is that it leaves so much to the imagination, allowing both you and your players to lay in immense amounts of fractal complexity onto a simple geometric shape.

(Which is not to say that block maps are the be-all or end-all of utility at the gaming table. You can take my copy of Ed Bourelle’s Ptolus map when you pry it from my cold, dead hands.)

And when you miss that opportunity — when your mental image of the block map reduces each geometric shape to a single building — you’re robbing the city of its grandeur, its complexity, and its flexibility.

Take a moment to go back and look at the map of Kintargo, for example. Imagine what that city would look like if each block were, in fact, a single building. What you’ll probably end up with is a modest city still possessed of some good degree of size. But what you should actually end up with in your mind’s eye is this:

Sun Tzu said:

As for deploying the army and fathoming the enemy: (…) After crossing rivers you must distance yourself from them. If the enemy is forging a river to advance, do not confront them in the water. When half their forces have crossed, it will be advantageous to strike them. If you want to engage the enemy in battle, do not array your forces near the river to confront the invader but look for tenable ground and occupy the heights.

Having some basic tactical acumen is a skill which I think is simultaneously overvalued and undervalued for Game Masters.

Undervalued in part because there’s a prominent segment of the hobby that snootily holds its nose in the air and tries to draw a line between “roleplaying” and combat. (Which is weird, because mortal danger is a thing which artists have used to explore character since the dawn of narrative, and it feels more likely that you just aren’t very good at using combat in your roleplaying games than it is that roleplaying games are this special snowflake in which heightened stakes don’t have the same effect they do everywhere else.) And also because some gamers don’t feel that tactical knowledge is useful unless you’re playing a game with lots of “tactical rules”. (Whereas, in my experience, the less mechanical support you have for tactics, the more important it is for the GM to be familiar with them.)

Overvalued because there’s another segment of the hobby which places tactics on kind of a holy altar above all other concerns. (And there’s a chunk of this group which is not really interested in actual tactics at all, but rather in a very specific flavor of mechanical manipulation. A surprising number of these don’t actually spend much or any time playing at all, but do enjoy spinning spherical cows whenever they get the chance.) I’ve even met would-be GMs who don’t take the plunge because they believe they need to be able to match tactical wits with their players and feel as if they won’t be up to the task.

The thing about tactics in an RPG when you’re the GM is that there are four simple truths which make your relative tactical mastery (compared to the players) almost irrelevant:

1. Just keep throwing more bad guys at the problem until you reach a tactical equilibrium. Maybe some other GM could challenge your players with five bad guys and you need nine of them. It doesn’t matter because (a) that other GM isn’t here and (b) you’re successfully challenging them.
2. If your players create some tactical conundrum that you can’t figure out how to overcome, simply have your NPCs do whatever it is that they’re doing. Your players will show you how to beat their own best tactics.
3. Encounters are cheap and your failure is the group’s success. You don’t want every encounter to be a pushover, but if you avoid the My Precious Encounter™ method of prep (and you should anyway, right?) then nothing of real value is “lost” if you throw up the occasional tactical dud, particularly since your players will be cheering their victory as they move on to the next encounter.
4. You’ll get better with practice.

And as you get better with practice, you will find that some basic tactical acumen is valuable to have tucked away in your GM’s toolkit. When applied properly, it creates more interesting and varied encounters. Tactical thinking is, ultimately, creative thinking. And by presenting a variety of tactics, you will provoke creativity in your players.

The good news is that, in my experience, a little bit goes a long way here. Whole libraries full of books have been written about tactics, but in practice you only need a handful of basic techniques. (This is particularly true because you can dial difficulty with the number of opponents in addition to your own tactical genius.)

HALF ACROSS THE RIVER

As Tee was working to release Dominic from his harness, however, Tor suddenly gave a cry and drew his sword: The troughs of ooze were beginning to undulate. Tee whirled and drew her dragon pistol, blasting at the surface of the trough to her left. As she did so, the motions of the ooze became great waves which sickeningly shuddered their way from one end of the troughs to the other.

Here’s one such tactical technique: Engage the PCs when half of them have crossed the river.

This doesn’t have to be an actual river, of course. In the current session the “river” is the rope the PCs are using to climb down into the sinkhole: Tee and Tor climb down the rope and then, just after Dominic has been lowered but before he’s released from the harness, the oozes attack. Tee and Tor have crossed the river; Dominic is in the water; and the rest of the party (plus their goblin allies!) are still on the far side of the river.

There was a similar dilemma – also featuring height – back in Session 11 (when the PCs needed to climb down into the ruined fungal garden).

This tactical technique creates a great deal of complication at the very beginning of the fight. It can prevent PCs from achieving their ideal or “clean” engagement (whether that’s something they’ve carefully planned out or just the routine which has become habitual for them). It also forces the PCs to deal with whatever the “river” is dynamically while under the intense time constraints which are naturally part of the combat system.

A couple of things to keep in mind when using this technique:

First, don’t attack too soon. If you attack as soon as the first PC crosses the river, it can be too easy for them to pull back. Let several of the PCs commit themselves across the transition and then attack (from hiding, from the next room, from the Ethereal Plane, whatever). Roughly half the party is a good rule of thumb, but won’t necessarily apply in all circumstances.

Second, remember that the attack can also target the characters who haven’t made the transition yet. You can even occasionally have bad guys hit both sides of the “river” simultaneously. (This can create a tougher fight, but can, paradoxically, actually result in less tactical complexity, as the PCs will usually just settle into two largely separate fights on each side of the “river”.)

Third, make sure that the bad guys take advantage of the “river” to best effect. (If it’s a literal river, for example, maybe they push the PCs into it when they charge.) This works particularly well if the bad guys have special abilities that are enhanced by the “river”, take advantage of the “river”, or allow them to ignore the “river”. (This often happens naturally in fantasy settings because bad guys are often themed to their environment; oozes in a cavern of ooze, for example.)

SETUP

There was trepidation among those standing at the edge of the sinkhole and surrounded by rotting fungus, sickly slime, and malformed corpses. Tee, in particular, harbored deep misgivings. To her the sinkhole was filled with a horrible foreboding and a sense of nameless doom.

Unless the bad guys are proactively pursuing the PCs, I tend to spend little or no time prepping tactics for them ahead of time. I find it leads to a lot of wasted prep and I think it’s simply far more interesting to tactically react in real time to what the PCs are doing. That’s one of the reasons this sort of Swiss Army knife of tactical techniques is so useful: You just spin out whatever’s appropriate while actively playing the NPCs.

This particular technique is great because it often doesn’t require any setup at all. The PCs will usually do it to themselves. You can see that with the rope in the current session. If you think back to the near TPK in Session 7, that was due to the players allowing themselves to become sufficiently separated in featureless water that they had effectively “crossed the river” and could only reach each other with time-consuming difficulty.

Later in the campaign, the group got their hands on a ring of teleport. I was initially concerned that easy, unlimited access to teleport magic might be too powerful for where the campaign was at. But since the entire party can’t teleport in a single use of the ring, it turns out the more aggressive they get with using the ring tactically, the more likely they are to “cross the river” as the characters in the initial teleport desperately try to maintain a beachhead during the long rounds it takes for the wearer of the ring to cycle back and forth. (Or, conversely, hold out during the teleport-enabled retreat.)

So all you need to do is keep your eyes open: When the PCs have stretched themselves out and effectively separated themselves across a barrier requiring time, effort, or both to cross, that’s your “river”. And that’s when the bad guys should attack!

Blood Terrors appear to be immortal, and are often found as tomb guardians in the cyclopean barrows of the Tyrannis Gígās (the Tyrant Giants). Long mistaken for some sort of transformation of the Tyrannis’ skyldur (their human serfs or chattel), the true nature of the Blood Terrors was rediscovered when the long-forgotten Idol of the Beast was recovered among the island kingdoms of the south. What had once sealed the Beast’s connection to this world now became a conduit through which its will could be made manifest and around which new cults could arise in dim memory of a primitive and bestial past.

Blood Terrors are a pure extrusion of the Blood of the Beast. Their glistening bodies — with skin-less musculature defined by clotted coagulations — boil with a raw, powerful rage.

BLOOD TERRORS (CR 6): 60 hp (8d8+24), AC 19, claws +11/+11 (2d6+4), Save +9, Ability DC 16.
Str 16, Dex 12, Con 18, Int 10, Wis 14, Cha 10
Skills: Balance +9, Climb +11

Blood Spray (Ex): Works like a grease spell. Persists for 1 minute. Triggered as immediate action if injured. Does not affect other creatures of the Beast.

Blood Blight (Su): 1/day, exude a 20 ft.-radius mist of blood that acts like unholy blight (3d8 points of damage; sickened for 1d4 rounds). Will save halves damage and negates sickened. (Sickened is -2 to all action checks.)

Immune poison
Resist acid 10, cold 10, fire 10
Telepathy 100 ft.

This stat block is designed for use with Legends & Labyrinths. It can be used with 3rd Edition games without modification.

This material is covered under the Open Game License.

Go to Part 1

ACTIVE SCANNING vs. ACTIVE SEARCHING

Since we’re discussing perception-type tests, let’s swap from passive perception tests to active perception tests for a little coda of sorts.

When it comes to active perception tests, there is a distinction between what I’m going to call searching (tossing a room, feeling for hidden seams on the wall, running your fingers under the edge of a table) and scanning (peering out into the darkness beyond your campfire, doing a manual spectrum-analysis with the ship’s sensors, holding your breath and listening intently).

This distinction between searching and scanning is one that I find most games either struggle with or ignore entirely, and I think this also reflects common GMing practice. I didn’t fully grok the distinction myself until it got repeatedly pushed in my face running the Tomb of Horrors: Trapped in a cycle of paranoia and terror, the players wanted to search for traps without touching anything (because touching it could trigger the very disaster they were trying to avoid).

In combination with passive perception, this essentially creates three tiers of perception:

• Not actively looking. (Passive Perception)
• Actively looking, but not physically interacting. (Scanning)
• Actively looking while physically interacting. (Searching)

(I use the word “physically” here, but the same conceptual breakdown can apply to non-physical scenarios: For example, the difference between noticing a hostile malware attack, actively scanning a program without loading it into memory, and actively scanning a program while running it. Or unexpectedly noticing that a girl on the far side of the bar is smiling at you vs. specifically scanning a social event in order to identify the Skrull shapeshifter vs. actually joining the party and talking to people to see if you can get the Skrull to slip up.)

These conceptual tiers exist even when the system doesn’t necessarily distinguish between them, so I’ve found it useful, when approaching a new system, to give a little thought to how I want to handle them.

For example, 3^rd Edition D&D distinguishes between passive perception (Listen/Spot checks) and active perception with physical interaction (Search checks). You can also have active perception at a distance if you spend an action to take an additional Listen/Spot check. For my house rules, I stated that passive Spot checks can be made against Search DCs at a -20 penalty and that Search checks could be made without physical interaction at a -10 penalty. (Collectively, this creates a zone of overlap between the skills and provides guidance for the previously uncovered zone between the two.)

DIVIDED PERCEPTION

As the example of D&D suggests, the difference between passive perception, scanning, and searching is not the only way perception skills can be divided. They are also often divided by different methods of perception (Listen vs. Spot, for example). In other cases, there may be only one skill, but it may come baked with a preconception about which sense(s) are involved in perception (Call of Cthulhu, for example, only has a Spot Hidden skill).

Regardless, I think it’s important not to get stuck on the idea that sight is the only sense that can be used to notice things. Get sound and scent and touch involved.

Also give some thought to how you can adjudicate situations in which the “wrong” sense is used to perceive something. Can you “hear” a secret door, for example? Maybe if there’s an unusual movement of air or some dim and distant sound echoing from beyond it. Normally you’d expect to detect an invisible person by listening for them, but if you were attentive enough couldn’t you perhaps notice the slight depression of the carpet beneath their feet?

In the case of D&D, I simply applied appropriate penalties for this sort of thing as the situation warranted. I eventually got tired of the divide between Listen and Spot for a number of different reasons (low utility from the division, causes problems with stealthy approaches, chews up skill points, etc.) and conflated them into a single Perception skill. This required figuring out what the effective loss of a particular sense would entail (not being able to see the invisible; not being able to hear in a zone of supernatural silence) and after some experimentation I went with a simple -10 penalty per sense you’re effectively lacking against a particular target.

Pathfinder went even further, conflating Listen, Spot, and Search all into a single Perception skill. But this actually provides something of a cautionary tale, because they failed to clearly establish a methodology for passive vs. active Perception tests, and thus rather bungled the result: If you strictly follow the rules as written, you don’t actively search for traps in Pathfinder. Perception tests default to being reactive (i.e. passive) and nothing in the rules for traps overrides that default. This does not appear to have actually been the designer’s intention, however, because, among other things, there’s a class ability which allows the Rogue to reactively notice traps they come within 10 feet of (which would be meaningless if that was, in fact, the default rule for all characters).

The point here is not that there needs to be a mechanical distinction between passive perception and active searching or between hearing and seeing or any other such division. Maybe such distinctions aren’t relevant to you or meaningful within the abstraction of the mechanics in the system you’re using. Or if there is a mechanical distinction, maybe that isn’t reflected in varying difficulty levels (as in my 3^rd Edition D&D house rules). D&D 5^th Edition, for example, distinguishes between passive perception and active perception (the former using a flat value vs. DC, the latter using a random roll vs. DC), but doesn’t vary the difficulty of the check based on whether you’re standing in the doorway looking into a room or actively tossing the joint.

The point is that these broad conceptual distinctions will arise naturally out of fiction-first declarations of intention and method during play, and because perception-type tasks are so ubiquitous and so frequent, you are going to want to have a very clear procedure for handling them in a way that both maximizes their effect and cleanly keeps the game moving forward.

NEXT: Social Skills