Monday, 19 May 2014

Generative Hexcrawling

Following on from JDJarvis's interesting recent post on exploration, I've been thinking today about what I'm going to call Generative Hexcrawling - or, to put it more bluntly, creating a rudimentary system to make simple exploration or searching useful and interesting. In particular, I'm trying here to make a system that can be used when the PCs engage in exploring a wide area looking for interesting stuff - particularly in an Indiana Jones, "Let's search for weird ancient ruins and their contents deep in the jungle/desert/mountains" type affairs.

So here goes. The basic concept is based around the Exploring Day. The Exploring Day is broken into two segments, morning and afternoon, although you could divide it into more segments as appropriate.

In two segments, a certain area can be explored. I'm going to suggest 1 hex on the basis of a 1 mile hex-map, although this will depend on the geography. (Exploring 1 square mile of jungle versus one square mile of desert is a vastly different proposition.)

Each segment spent exploring an area, the DM rolls 4d6. If the first d6 results in a 1, there is an encounter. If the second d6 results in a 1, a minor site is discovered. If the third d6 results in a 1, an inhabited ruin is discovered. If the fourth d6 results in a 1, the party gets lost and ends up exiting the hex at a randomly determined edge. These can obviously be tweaked or modified as desired.

An 'encounter' result is a typical random encounter (although you could introduce elements like "somebody breaks a leg", "somebody gets bitten by a poisonous spider", etc.). A 'site' result is a small location, possibly with treasure or a Gamma World style MYSTICAL ANCIENT ARTIFACTTM, possibly with a monster. An 'inhabited ruin' is a sizeable complex inhabited by a significant being or population (and probably mapped out using something like the fast and dirty AFF2 dungeon map generator).

You would then need random tables for encounters, sites, MYSTICAL ANCIENT ARTIFACTSTM, and inhabited ruins, with sub-tables for more details such as treasure types and magical features. I won't do this properly at this stage, but for illustration's sake, I'll give some d6 tables, assuming an area of jungle is being explored:

1. Carnivorous apes
2. Giant beetle
3. Giant centipede
4. NPC explorers
5. Tyrannosaur
6. Yuan-ti

1. Monolith
2. Cave
3. Shrine
4. Abandoned village
5. Tower
6. Cairn

Inhabited Ruin
1. Cultists
2. Dragon
3. Degenerate tribe
4. Oozes
5. Hook horrors
6. Manscorpions

Once two segments have been spent exploring a hex, it is 'exhausted' and does not reveal any more secrets, although encounters will still occur in it.

Rather than exploring, if the PCs have no rations, they can spend a segment foraging for a day's worth of food (thus a day spent foraging allows two days of further exploration). During this time, encounters can occur, though not discoveries of sites or ruins.

Each hex successfully exhausted gives a 100 XP bonus to each PC.


  1. I think the first thing you'd need to do is come up with rules for aerial reconnaissance. Even a simple levitation spell can really cut down on search time and one thing I know I've learned is to always think of flying, as it is always one of the most popular spells.

    Now is where i get obscure on the subject. I remember there being an Avalon Hill game in the 70s called Source of the Nile, which was an early attempt to do this, and through the wonders of the internet, here it is and you might find it interesting.

    1. Haha, well, maybe not the first thing, but yes, that's a good point. I'll take a look at the Source of the Nile - thanks!

  2. This is cool! Partially inspired by your older posts about how much stuff is in hexes, I'm working on something very much like this as well. The issue I'm still mulling over is dealing with the "exhaustion" thing. I'm thinking in a context where more than one group might be exploring, so I'd like for one group to be able to find nothing, and another to stumble onto something. On the other hand, I don't want people to find endless ancient ruins in one hex, so I'm trying to figure out a "diminishing likelihood of finding stuff but never get to zero chance" that works.

    1. Thanks. I know what you mean. Maybe after you've spent a certain period of time exploring one hex, you simply roll more d6s. So you spend two segments exploring where the chance of discovering things is 1 in 6 for each discovery type (encounter, site, ruin). After that, you roll 2d6 for each discovery type and both have to come up as a 1.

    2. Ah, that's clever. Theoretically there's always a chance, but it gets vanishingly small pretty quick. I think I'm even okay with each progression starting fresh when a new group gets there (I think this would only get ridiculous if you have more than 3 or 4 groups exploring the same hex and all finding something).

      Oh, I've also got a little more wiggle room because I'm thinking in terms of 6-mile hexes, so there can be lots and lots of stuff in there. Thanks for the idea, I'll let you know what I end up with.