The Alexandrian

Isle of Dread

Not to be confused with hexcrawling, hex-clearing is the process by which monsters and other hostile forces were cleared out of a hex in preparation for a stronghold to be constructed. Clearing a hex was the first step towards bringing civilization to an uncivilized portion of the world. It was also the transitional point between the low-level activities of monster slaying and the high-level activities of realms management. It is one of the oldest game structures in D&D, yet I feel comfortable saying that probably 99% of all current D&D players have never done it.

In pursuit of a tangentially-related project, I decided to do a brief survey of the extant hex-clearing procedures in old school D&D. I offer them here in the thought that they might be of use to a wider audience.

OD&D HEX-CLEARING

Hex Scale: 5 miles

  1. Referee rolls a die to determine if there is a monster encountered.
  2. If encountered monster is defeated or if no monster is encountered, the hex is cleared.
  3. Territory up to 20 miles distant from an inhabited stronghold may be kept clear of monsters once cleared.

AD&D HEX-CLEARING

Hex Scale: 1 mile / 30 miles

CLEARING HEXES

  1. Make wandering monster check.
  2. If encountered monster is defeated or if no monster is encountered, the hex is cleared.

Once cleared, hexes will remain cleared, except:

  1. Once per day, check to see if a monster has wandered into an uncleared border hex.
  2. Once per week, check to see if one of these monsters has wandered into the cleared territory.

Patrols: If regular (1/week) patrols from a stronghold are made through a cleared territory, the check to see if a monster has wandered into a border hex is made only once per week.

CONSTRUCTING THE STRONGHOLD

  1. Must map and clear the central hex (location of stronghold) and six surrounding hexes.
  2. Unless 7 hexes are actively patrolled, there is a 1 in 20 chance per day that a monster will enter the area.

GYGAXIAN VAGUERY – PATROLS

Because Gygax was objectively terrible at writing rulebooks, the rules above are actually incomplete. They overlap with a different set of incomplete rules which directly contradict the first set of rules. If you use this second set of rules, a cleared hex that is being patrolled should be handled in this way:

  1. Once per week, check on the Uinhabited/Wilderness encounter table to see if a monster enters the cleared territory.
  2. Once per week, also check on the Inhabited table. Or, if there is a road, check three times on the Inhabited encounter table.

Zone of Civilization: If a territory is cleared to a 30 mile radius [should probably be 30 mile diameter, filling the large hex that the stronghold is at the center of], make ONLY the second type of checks, but ignore all unfavorable checks except once per month.

Reversion to Wilderness: If patrols are not kept up, the territory automatically reverts to wilderness status. “Unless the lands around it are all inhabited and patrolled” in which case “all of the unsavory monsters from the surrounding territory will come to make it a haven for themselves.” [So it won’t revert to wilderness, it will just really revert to wilderness.]

RULES CYCLOPEDIA – HEX-CLEARING

Hex Scale: 8 miles / 24 miles

Clearing the Hex: You just… do it. “An area is considered clear when all significant monsters in the area have been killed, driven out, or persuaded (through bribery, threats, persuasion, or mutual-defense agreements) to leave the PC’s subjects alone.” There are no further guidelines.

Constructing the Stronghold: Clear the 8-mile hex in which the stronghold is being built.

Patrols: Cleared areas automatically remain free of monsters as long as they are patrolled.

  • Patrols can range 24 miles from a stronghold in clear terrain.
  • Jungles, swamps, and mountains require a garrison every 8 miles.

There are more detailed rules for dominion management, but they don’t really pertain to hex clearing.

EXPERT SET VARIATIONS

  • Hex scale is not clearly defined. (Isle of Dread, the sample adventure included in the set, uses 24 mile and 6 mile hexes.)
  • Patrol ranges are limited to 18 miles and 6 miles (instead of 24 miles and 8 miles).
  • The 18 mile limit of patrols matches the 18 miles an encumbered character can travel on foot in a day. The Rules Cyclopedia oddly maintains the same rule for determining overland movement rates (divide by 5 to determine the number of miles a character can travel over clear terrain per day, and therefore 90’ divided by 5 = 18 miles per day), but the Traveling Rates By Terrain table doesn’t follow that rule and instead uses values calculated to divide evenly into hexes (so an encumbered character only travels 12 miles per day in clear terrain).

JUDGES GUILD – HEX-CLEARING

Hex Scale: 5 miles

As I’ve mentioned in the past, Judges Guilds’ hexcrawl procedures and management had a major impact on the game. Virtually all of OD&D’s hexcrawling procedures, for example, were abandoned by AD&D in favor of systems clearly drawing from Judges Guild material. This was somewhat less true when it comes to hex-clearing, but I thought reviewing the material from the Ready Ref sheets might be useful. In this case, it largely was not:

Constructing the Stronghold: Clear 4 hexes radiating from the stronghold’s hex.

Patrols: Automatically keep hexes clear of monsters, except for mountains, swamps, and dense woods.

Back to Reactions to OD&D

10 Responses to “Reactions to OD&D – Hex-Clearing Procedures”

  1. Eric Scheid says:

    Thanks for compiling this summary across editions.

    Now to ponder what these imply for lower-level adventuring parties .. e.g. supply of jobs & bounties.

    Also… what in your experience was the approximate timeline for fully clearing a region? For example: how many weeks or months of patrols would be needed to get full coverage?

  2. Justin Alexander says:

    My general impression is that the clearing process was meant to be “hands on” for the PCs: You went out and you did it, following general hexcrawl procedures. Given travel time, etc. you could probably expect to clear your initial area in a few weeks or less.

    The interesting question for patrolling cleared territory is less the amount of time it takes and more how large the force needs to be to pull it off. As I typed this, though, I realized that there’s actually a table for patrol encounters in the AD&D1 DMG: “Patrols will be commanded by a fighter (or ranger, where applicable) of from 6th to 8th level, with a lieutenant of from 4th to 5th level, and a serjeant of 2nd or 3rd level. There will be 3 to 4 1st level men and from 13 to 24 soldiers (men-at-arms) forming the main body. (…) Accompanying each patrol will be a cleric (40%) of 6th or 7th level or a magic-user (60%) of 5th to 8th level.”

    If you cross-reference with the cost of employing such a force, you’ll discover that it’s relatively expensive.

  3. Tom says:

    It’s an interesting part of the game that I’d never heard of, I can see this being used by my group for a “taming the wilderness” type campaign. Thanks!

  4. Beoric says:

    Have you ever seen anybody deal with the problem that in hills or forest you can see very little of the hex you are clearing?

    I mean, on the plains you can see right to the horizon, so if you stand in the centre of a 6 mile hex you can see pretty much the whole thing; but in a forest where you can see maybe 150 feet, if you stand in the centre you can see perhaps 1/400 of the hex. How long would it take to clear the hex if you have to criss-cross it many times to know if you had missed anything?

  5. Eric Scheid says:

    Some quick back of the envelope calculations for the AD&D scenario (30 mile region hex, with 1 mile sub-hexes) …

    A hex which is 30 miles across (side to side) has an area of 779 sq. miles. A hex which is 1 mile across (side to side) has an area of 0.866 sq. miles. Therefore, there are 779 ÷ 0.866 one-mile hexes in a 30 mile hex .. 900 one-mile hexes. (What, you want me to count them instead?)

    Across clear ground, no interruptions, a patrol can cover about 24 miles per day. It would take 1 patrol 37.5 days to enter every small hex. A bit over 5 weeks, plus inevitable delays, so 6 weeks. To visit every hex once per week, would require 5.3 patrols to be simultaneously active.

    There are 16 smaller hexes along each larger hex side, for a total perimeter of 96 hexes. Alternatively, the straight-line perimeter of a 30 mile diameter hex is 103 miles. So a border patrol would take 4.3 days.

    Assuming a 2 in 20 chance of a wandering monster for general/open terrain, that makes about 9 border hexes per week reverting to wilderness. That’ll keep that border patrol busy.

    That’s open terrain. For light forest/scrub: 2× the travel time; rough forest / hills it’s 3× travel time, and also 2× encounter chance. Heavy forest is 4× travel time, 2× encounters. Swamp is 4× travel time, 4× encounters.

    Clearing a swamp hex is gonna be hell — 150 days to simply visit every sub-hex once, by which time 40% have become re-infested, and ×5 continuous border patrols re-clearing 38 border sub-hexes each week.

    Or something like that.

    Of course, one would hope that not all six side of the hexagon are facing wilderness, so adjust downwards.

    So, I can certainly see PCs of name level being quite hands on in clearing the hex. Also, I can see that even low level PCs visiting a wilderness outpost could certainly pick up some overflow work from the NPCs of name level clearing or maintaining that hex. (Which is a sneaky show-don’t-tell method of preparing the players on what is needed for when they do reach name level).

  6. DanDare2050 says:

    Our open table group has had a few sessions where this has been happening. The older DMs know the old rules and we have adopted a “near enough is good enough” game structure. A group of players have gained ownership of a swamp and have indeed been working on clearing it out. Not easy.

  7. Yukiomo says:

    Have you done any surveys of new hex-clearing procedures (i.e., OSR-type products)? The only one I’m aware of is in the Lairs & Encounters supplement for ACKS. It has a basic system for estimating the number of lairs a hex might contain, integrated with the ACKS systems for proficiencies and hirelings.

  8. Justin Alexander says:

    @Yukiomo: I’ll have to check out Lairs & Encounters. I checked a number of retro-clone products (including the core ACKS rulebook which I was sure would have hex-clearing mechanics), and we surprised to find a complete paucity of them.

    It’s the one of the reasons I do all my true old-school gaming using the actual OD&D rulebooks: That’s where the good stuff is; the stuff that got left behind when RPGs went in a different direction.

    @Beoric: If you’re just using, for example, the basic OD&D system then you’d generally not have any uncertainty. The extra time required to clear a hex with difficult terrain would be modeled by the extra travel time required to enter/exit that hex.

    If you’re using something like my procedure for hexcrawling then, structurally speaking, you need to go to the hex in question and spend time just tooling around looking for the encounter.

    If you don’t find it, then you may assume that the hex is clear. Of course, that may not be the text. The GM may have generated an encounter in that hex and you just didn’t encounter it. In that case, expect your workers and/or citizens to be harassed by whatever threat you missed.

  9. DanDare2050 says:

    @Justin “the stuff that got left behind when RPGs went in a different direction”.

    The OD&D included actual changes in the nature of the game. Hex clearing was part of the establishing of a stronghold, which then led to geopolitics.

    However those game changes didn’t work well for player groups. It was usually an individual that owned their wizard tower, or keep or whatever.

    The “tiers of play” in new D&D seem not to be changes in type of game, but more combat over wider realms.

    Have you found ways for adventuring to segue into politics with a group of players? Are there game structures you think achieve this?

  10. Tom B says:

    Some of the math is a bit problematic.

    What about seasonality and terrain types considered in how pragmatic patrolling is? And foraging?

    In wet seasons, some areas would be impassable and even dangerous to patrol on horseback or foot. In dry seasons or desert like conditions, patrolling could be a problem without water sources. In winter, plowing your rangers or your light cavalry through 2′ of snow or 4′ of snow would really change the game as would iced rivers and streams (hazards). In tough climatic conditions, your troops might spend at least 1/3rd of their daylight hours decamping and recamping. Foraging would cut down the rate of travel for patrols by quite a bit. And being wet, doing big hills, heat, cold, etc. can fatigue or exhaust your patrols and their mounts.

    Then on the other side, if you can get altitude and a decent vantage, you can probably scan surrounding clear terrain for signs of any significant threats (goblin camp, lazing land shark, whatever). With any form of magic or optics that you’d allow, you could vastly extend the distance from the patrol itself would cover. Also, a cavalry patrol can split off small detachments to widen their area of situational awareness (more hazardous in rough country, but in open country or gently rolling moors or hills, you could probably risk that.

    I’d assume that any sizable threats could be seen at 500 yards in clear terrain and if you scattered out some outriders or foot scouts to say 400 yards, that’d give you and 1800 yard width. That’s about the width of a mile hex in clear terrain. So one pass through at a walk would probably take 30 minutes without rushing or on horseback, maybe 20 minutes.

    With the right optics or a big enough target (enemy pallisade fort full of kobolds for instance or a wrecked city next to a lonely mountain that shows dragonsign…) plus some altitude (moving some of your scouts along ridgelines or just beneath them) could give you a couple of miles vision in either direction for big objects or groups.

    Additionally, when you are patrolling, you are nuts if you don’t have:
    a) some locals (even cooperating humanoids)
    b) some good trackers/rangers/scouts
    c) tracking dogs (even the Swedes use these with their air force SF teams that protect installation and airbases – the dogs are critical to tracking and finding any Spetznaz dropped behind the lines to attack airbases or storage locations)
    f) magic or a trained bird that can let you see the area from above and the patrol can vector into the location of anything interesting (a fancier approach than the dog, but aerial servailance is super useful).
    g) Your scouts can talk to locals (maybe with a nature priest or druid, you can do that with animals) to get information (the old hermit said… or the wolf saw these two legs near the lake…). That kind of extra eyes passing on info could be useful.

    And your scouts will not need to see every inch or terrain to determine where critters had been – some signs of certain grazing patterns or footprints in one spot might direct patrolling towards a nearby-but-not-immediately-visible enemy formation or camp.

    You aren’t looking to catch every single monster or humanoid or bandit. They won’t threaten a village or a fortification or a patrol. You are looking for larger groups, bigger monsters, etc. so they correspondingly have wider foraging needs, may generate more smoke in the day or fire at night, kills of animals might suggest who killed them and which way they were taken, etc.

    So really, patrolling can cover a lot more time and distance than the various rules cover.

    On the other hand, I’ve been in forests thick enough that 1/5th or worse movement was involved (not counting getting lost) and where the longest clear line of site might have been 50 yards (most of the time 0-15 yards). That’d be brutal to try to fully scout, much like a swamp (good lord).

    However, the counterpoint there is that if it impairs your passage, it likely impairs the threat’s movements too. They either have to blaze or break their way through the undergrowth or wade through the gunk, often leading signs and being noisy, or they have to avoid the very close terrain in favour of some clearings, paths, etc, which, one located, can allow your patrols to cover more distance.

    Around where I live, near town, we have fields and medium forest (mixed conifer and broad leaf trees and underbrush). But go 50 km out and you’re into very undulating, rocky land covered in trees. In most of the hollows, you either have more trees, mushy ground, or an outright pond or little lake. Navigation in that setting is brutal without roads and even climging a tree wouldn’t help much. And in the space of 500m in a line, you might cover 3 different raised areas, two with trees, one bare, and the two hollows might be a swamp mess in one and a bit of open water (stream or pond) that you can’t walk through. Trying to scout this is horrible, but it horrible for all so many bad guys won’t locate to that zone either or will be near any trails or cleared areas making finding them easier. I used to live in a desert area where I could see as far as the horizon and the weeds and cactus were only about 6″ high at most but there wasn’t much water and a cactus could go right up through your running shoe sole into your foot (did that). No hiding there.

    I think you have to assume your patrols will spread as best they can (I assume a patrol of 10 to 20) and cover more ground while keeping some contact.

    You should also assume that the odds are many critters and humanoids will look to the same easier paths/routes that your scouts will identify so the fact that 10-70% of the hex is hard to access (10% maybe in clear, 70% in dense woods) is not such a big issue – because the more open areas will attract both the patrol and other creatures or species travelling upon it.

    With roughly 780 1 mi hexes out of a 30 mi hex, you can probably clear that with 1 patrol and an open terrain type in 28 days or so with assuming 10% really thick terrain doesn’t need traversed. With 4 patrols, you can manage it in a week.

    And it might be paradoxical but it might take a medium woods hex the less time than you think – because the % of too much bother to traverse space would offset the challenge of moving in the medium density forest. Now, the smaller patrol radius, you might end up with the x2 modifier or x 1.5 or x2.5 depending on specifics. So 4 patrols might still clear this hex in 2 weeks.

    And another point:

    If you have powerful patrols and frequent and they mark their territory and leave some examples of what happens to unwanted trespassers, it might happen that any threat that wanders in might leave when they realize that.

    My post is kind of all over the place, but there’s a lot of depth you can put into this. And it will make the project perhaps more fun to have it feel more gritty.

    TomB

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