The 3 Mile Hex - The Natural Unit for Exploration

There will be interludes between the AD&D Appraisal series, to keep my own writing motivation going.

I was going to do a 3-mile hex post outlining the virtues of it, but turns out Silverarm did that already and stole all my points (even down to the "Outdoor Survival also uses 3 miles") and added more points I wasn't aware of myself. So go read that excellent piece and come back here.

What I instead want to talk about is how the 3 mile hex is a very close fit to our natural sense of distance and visualisation and how the that makes the 3-mile hex the perfect blend between immersion and usable game artifact and how to actually bring that into your game. 

Minaria hexmap. Scale: 1 hex = 50 miles. Not what we're going for here.

A while back, Noisms contemplated the difficulty of creating a sense of wonder in journeys. The difficulty with journeys in RPGs is the scale of it. It becomes too big, and thus too abstract, to visualize, to immerse oneself into. 

I tried, unsuccessfully I think, to argue for why I liked hexcrawls for this purpose. They create a bounded experience, a scene one traverses through so to speak. It allows us to zoom in and create a 360 degree dome of visualization that can be described, walked through, wondered at, whilst also providing glimpses of the horizon, what lies in the next hex. All strong elements for that experience of exploration, wonder and discovery.

If we treat hexes simply as a measure of distance, we've missed their main utility. A hex is basically a unit-of-something-interesting. Something that gives us a reason to zoom in and spend a moment, or many, on this unit of interest, whether it be a village, monster, ruin, etc., as opposed to simply pressing fast-forward and skipping past.

Now, the 6-mile hex has long been a popular standard. But I find it lacking for this purpose. A 6 mile hex is just too big to be a unit of exploration that is actually gameable in-character. It can hold too many things of interest and it is too easy to miss things in a 6 mile hex. Manhattan fits inside a 6-mile hex. At this resolution, we can no longer create the dome of visualization where we can rightly get a sense of the hex as a scene unfolding before our inner eye. Abstraction begins to kick in.

Staring into the neighbouring hexes

The Naturalism of the 3 mile hex

The 3 mile hex however, hits that mark much better. 

For one, it is the distance an unencumbered person walks in an hour of open terrain. 

Secondly, it's also the distance to the horizon at sea level.

This grants us two natural advantages, because now most everyone will have an innate sense of distance in the visual field, as well as distance over time, in terms of walking. In other words, 3 miles is something we already have a natural sense of once we make those two translations.

From the perspective of the PCs, the 3 mile hex forms a dome that contains their immediate surroundings and in this the way the entirety of the hex is directly accessible to their perception. Not in the sense that all sites are necessarily perceivable (although in open terrain they would be), but that they are nonetheless within that field of perception of what you could see if the terrain were fully open. 

Ie "to the east, the open fields stretch to the horizon. To the west, the woods. Somewhere in there, no further than you can see to the east, lies the tower of the woodland warlock."

Exploring within a 3-mile hex is also accessible to our sense of space and time. Everything inside a 3 mile hex is on average around a 30 minute walk, an hour max. It's an easy thing to eyeball within the hour.

There is also natural language for 3 miles. A league. Which is derived from how long a regular person can walk in an hour. That means when people in game say "4 leagues to the south", it translates directly to your hex map and simultaneously gives you an idea of how long it takes to get there.

The centre of the hex gives line of sight halfway into to the neighbouring hexes (again assuming open terrain). Which means finding a high point near the centre of the hex and looking to the horizon gives you a very meaningful frame of reference, both in-character and in-game, for deciding where to go from next.

The navigation and exploration becomes tied to what your character actually sees, whilst being consistent with the game artifacts way of unitising that.

The Hexes Go Ever On

The 3 mile hex as a game artifact

Let's try and tie these observations on the naturalism of the 3-mile hex into the game system and see how it fits. 

3 miles is the rough average distance between villages in settled farmlands in medieval Europe. This gives us a nice baseline for a 3-mile hex also being a singular unit-of-interest. So besides the sensory immersion perspective, we also get a good meta-gaming reason for zooming into this scale of resolution.

As mentioned, it is the distance an unencumbered person walks in an hour of open terrain.
An hour is also a good resolution for unit of time for wilderness exploration, where a unit of time is the time needed for "one significant action", in the same way a turn of 10 minutes is the time it takes to make a significant action for dungeon exploration.

This gives us a pleasant baseline whereby it takes

1 unit-of-time-for-a-significant-action
to traverse
1 unit-of-interest-in-space.

Which is not so different for why a league exists as a unit of distance in the first place.

And all this is, incidentally, also the largest scale at which sensory immersion and visualisation is still high.

"Very Rugged Terrain and Medium Encumbrance. We'll cross no more than three hexes per day of this, Master Frodo."

A formula for hex-travel

It's a commonly accepted assumption that characters can walk 8 hours a day, meaning they can traverse 8 hex of open terrain per day. This gives us a nice, but not too high, granularity, before we factor in encumbrance and terrain slowing you down. We can simply count the cost in hexes and round up any fractions of the result.

An example schematic employing four levels of encumbrance and BECMI terrain modifiers:

• No Encumbrance: 8 hexes

• Light Encumbrance (75%): -2 hexes  / 6 hexes

• Medium Encumbrance (50%): -4 hexes / 4 hexes

• Heavy Encumbrance (25%): -6 hexes / 2 hexes

And then apply terrain modifiers to that, rounding up fractions.

• Forest, Hill Desert: x2/3 (No enc.: 6 hexes, Light: 4, Medium: 3, Heavy: 2)

• Mountain, forest, jungle: x1/2 (No enc.: 4 hexes, Light: 3, Medium: 2, Heavy: 1)

Or, going a bit simpler, we could take the lovely Movement afoot in miles/day table from p58 of the 1e DMG and adapt it to counting 3-mile hexes per day:

Burden/ Terrain	Normal	Rugged	Very  Rugged
Light	8	6	4
Average	6	4	3
Heavy	4	3	2

I rather like this table. No calculation needed and it is super easy to scan. I also think two levels of added encumbrance is more than enough for any system.

If we are going through different terrains, we can also change the table a bit to count Hours per Hex instead of Hexes per Day. It doesn't give exactly the same results due to rounding issues, but I am ok with changes in terrain costing an extra or handwaving the extra hour to get there: 

Burden/ Terrain	Normal	Rugged	Very  Rugged
Light	1	1.5	2
Average	1.5	2	3
Heavy	2	3	4

Bringing it all together - Engaging the Hex

This means that in our hexplorations, we will likely traverse somewhere between 5 to 1 hexes pr day (3 probably being the most common), aka 5 to 1 scenes of interest to engage with in a travelling day. This is also a manageable number for a DM to visualise engaging with, and for the players to work with (although 5 is probably at the upper limit of scenes whilst still engaging interest).

And from here, the DM should be able to visualize what the hex-as-sensory-scene actually contains, even if not all of it is necessarily perceivable to the players, and try to bring words to the sensory dome that is the 3-mile hex they are travelling through over the course of 1 to 8 hours, bearing in mind any special landmarks or sites.

Bear in mind also that at the centre of the hex, barring large obstructions, they should be able to peer into any neighbouring hexes and orient from there on the next step.

Here's what I wrote in the DM's Handbook for Into the Unknown on bringing a scene to life:

3 FROM 5 Besides Vision try to include one or two from Hearing, Smell, and Touch. You don’t need to touch something in order to intuit what it might feel like if you did. Touch can also include wind and temperature.

KEEP IT TERSE Lengthy descriptions don’t necessarily immerse players. 3 to 5 brief but evocative images is all players need to to realize the scene in their own minds, and about as much as they can take in before it becomes counterproductive and they begin to tune out.

SHOW, DON’T TELL Telling the players how they feel about a scene won’t make them actually feel the mood. Painting an evocative image to induce atmosphere can speak a thousand words in this regard. Likewise, give the players observable clues and hints to make their own conclusions, rather than concluding

The Wilderness As A Scene

A wilderness scene unfolds at a scale of hours. Focus on the horizontal point of view rather than the map’s birds eye. A hex is its own point of interest to present – Think of it as a large room, with various features, being walked through.

WEATHER helps further immersion in the landscape.

SOMETHING SMALL, SOMETHING BIG Paint a panorama that focuses on the small and the big (“lichen grows on the rocks as you pass; in the distance the pillars of heaven tower over the horizon”) to give the scene a sense of both spaciousness and nearness.

Nothing inspires wonder like glancing across a 3-mile hex

Afterthoughts

Scale of the journey matters. If you are going to the other side of the continent, 3-mile hexes each played as a scene will be a drag. Which is also why, as Silverarm points out in his eulogy on the 3 mile hex, there is value in thinking small when making your sandbox, to create the sense of exploration and discovery. 

For long journeys, (say, to travel from one sandbox to another), I advocate 24-mile hexes, since that is the length one travels in a day unencumbered in open terrain. And just as the 3-mile hex is fitting for how it aligns with the 1 hour unit of overland travel, 1 day of travel is a fitting unit of time for long journeys.

It also helps to understand the map when you can look at it and say "ok, the number of hexes between these two is how many days it would take to walk in open terrain." Again, harmonising game artifacts with our naturalised perceptions of distance. Perhaps I will do a follow-up post on the merits of the 24 mile hex.

Once you are in the sandbox you want to be in though, 3 miles is king.

PS. I went back and edited the numbers in the table. The original weren't scaling properly at the heavy end.