Monday, November 24, 2014

The "Evolve Rules" Table

Hidden in a secret cobweb-filled vault under TSR's former Lake Geneva headquarters we found a curious stone tablet of eldritch origin that had been laboriously inscribed with the following:

To produce a new edition of the rules, start with the current edition, roll on this table 3 times (re-rolling duplicates), and find new artists.

1Add a new playable race, roll on any of the current edition's random encounter table for race.
2Remove a playable race without explanation OR re-roll level limits for each class using 2d6+2.
3Change monster hit dice from d6 to d8, d8 to d10, d10 to d6 as compared with the current edition.
4Add or remove specialist magic-users, depending on whether or not the current edition has them.
5Change how rangers pick their favored enemy; if there currently are no rangers, introduce them.
6Roll d6: 1-3 combat is Theatre of the Mind; 4-5 combat is on square grids; 6 combat is on hex grids.
7Number of books/boxed sets to spread new edition rules out over: 3d20-2, reroll 1s.
8Add only 0.5 to edition, not 1.

Apparently an (incomplete!) copy of the tablet was made by certain WotC delvers when they first explored the ruins of TSR after acquiring a deed to their holdings. It's unclear what mistakes they made in their transcription, but they must have made some...

Riffing on 2d6: Reaction Rolls

I've started to take a real liking to 2d6 as a dice mechanic. For the longest time I didn't actually care for it, I was a fan of rolling a d20 for almost everything. But I've spent a lot of time thinking about the classic reaction roll in D&D (inspired in part by this post) and the longer it sat around in my brain, so more useful the probabilities created by 2d6 seemed to get. Here's how that reaction roll works abstractly, at least in most D&D-variants (B/X D&D, page B24 for example):

2really bad2.78%
12really good2.78%

This has some nice properties. Obviously the "neutral" outcome is most likely which is probably just as well. After all, this is meant for a confrontation with a random pack of monsters who just popped around a corner. If both sides indeed "try to chat" that should probably lead to a temporary stalemate more often than not. Then there's a pretty decent chance for making "progress" in one direction or the other. I think that fits the "random negotiation" model again where both parties can usually feel that things are starting to slip before any actual stabbing occurs. Finally there's a pretty slim chance that things lead to immediate hostilities or immediate friendship. Neither of these should be very likely when you turn a corner and suddenly face a dozen kobolds: your side may be worried about being outnumbered, but their side should be worried about your big swords. So to me, this is just about perfect for monster reactions.

It's strange that Gary Gygax decided to mess with this for AD&D where reaction rolls are suddenly percentile-based. Here's what he (unenthusiastically in my opinion) proposes in the Dungeon Master's Guide (page 63), again abstracted a bit:

1-5really bad5%
26-45neutral, negative bias20%
56-75neutral, positive bias20%
96-100really good5%

What exactly are three versions of "neutral" good for except to complicate the table and to force the poor referee to be prepared for seven different outcomes to portray? Five different outcomes already enough of a workload! Also we get slightly increased chances for "really bad" and "really good" at the price of upping the total chance for "not sure yet" to 50% instead of 44.45%. That really only seems to lengthen the average time spent on the mechanic (negotiations take longer to conclude). As far as I am concerned, this is one of several cases where Gary was trying too hard to be "advanced" as it were.

If the point was to make the extreme outcomes more likely, he could have achieved a similar effect just by using different bins:

2-3really bad8.34%
11-12really good8.34%

I am not sure if I am the first person to propose this? Maybe Gary even tried it but decided that 8.34% is too much? Who knows with these things...

Interestingly the reaction roll comes in two variants in OD&D. The "monster reaction" variant was actually an even simpler 2d6 roll with only three possible outcomes (Vol 3, page 12):


This variant is also used in the Confusion spell (Vol 1, page 27). The variant with 5 outcomes (as above from B/X) was used only when recruiting monsters (Vol 1, page 12), not when encountering them.

Using the simpler OD&D table with three outcomes, there's yet another variant we could construct by attaching "special meaning" to rolling doubles. For each of the three outcomes there are two ways of rolling doubles: 1-1 and 2-2 for "really bad", 3-3 and 4-4 for "really neutral", 5-5 and 6-6 for "really good" as it were. It's easy to interpret "really bad" as "monsters attack" and "really good" as "monsters help" but what the heck does "really neutral" mean? Maybe that negotiations end right there and the monsters just decide to leave? Seems reasonable I guess. Opinions?

In terms of probabilities we now get something a bit more complicated to figure out, but it's not impossible. It is, however, a pain to put into a table because the "special outcomes" are not a contiguous range:

2-5really bad5.56%
6-8really neutral5.56%
9-12really good5.56%

So for the "non-neutral" outcomes, that's also close to what Gary did with his AD&D reaction roll. On top of that it's pretty cute to make doubles meaningful, at least I find it fun.

I don't know if this turns anybody else on to 2d6 but I sure had fun writing it all up. There's more in my brain regarding 2d6, at least the "turn undead" mechanic and using 2d6 for skill checks. We'll see when I have the time to write them up. In the meantime, I'd love to hear your take on 2d6 in general and reaction rolls in particular.

Update 2014/12/11: Who would have thunk it, there are still more variants on the reaction roll! I noticed this earlier today when reading this post over at DHBoggs' fascinating blog. The version he gives comes from the "New Easy-to-Master Dungeons & Dragons Game" but it's also in the Rules Cyclopedia (page 93). Here's my reproduction with percentages inserted as I've done for the other versions above:

2-3really bad8.34%
4-6neutral, negative bias33.33%
10-11neutral, positive bias13.89%
12really good2.78%

Given the historical precedent discussed above, those asymmetric ranges are certainly strange: Monsters are now more likely to attack than to be cooperative! (Maybe that's just as well, after all the later versions of the game seem to encourage combat more anyway.) The AD&D idea of "bias" is back again, so there's a good chance (a 47.22% chance in fact!) that you'll roll on this table at least twice before getting a result (the rules recommend stopping after three such rolls). Note, however, that there's no longer a "good" and "bad" category, only the extreme outcomes are actually possible.

Now if you think this is a bad table for the reaction roll, think again. Think hard! Because I am about to show you an even worse one. If my brain is any indication, we simply repress things we find horrible even if we grow up with them. Case in point, I played a long-ish campaign using the Rules Cyclopedia back when it came out. I thought I knew those rules pretty well. But when I first wrote this post, I couldn't remember this whacky reaction roll table at all. I must have repressed it!

But now open your 1983 Mentzer Basic Set, Dungeon Masters Rulebook, and turn to page 22. Yes, look at that triply-nested monstrosity. I won't even type it up, I'll just use a scan:

I know I certainly repressed that one. There's literally no record of this anywhere in my brain. And yet that's the D&D I grew up with, the D&D I played forever and ever before getting the Rules Cyclopedia. Did you repress it too? In protest, I'll leave the analysis of this table to someone else.

Sunday, November 23, 2014

The Trouble with Movement Rates

I am not sure why I suddenly had an urge to figure out how various editions of D&D handled movement rates for various creatures, but here's the result of my very brief study. I chose to focus on creatures that seem "familiar enough" to allow an "informed guess" of sorts, in other words I chose creatures I cared about for one reason or another. Here we go:


At first everything looks great, a wonderful consistency seems to rule across the entire 1970s and early 1980s. Then, however, the mischief becomes more obvious. Halflings used to be just a fast as elves in Chainmail, but their feet move a lot slower in AD&D and B/X; curiously neither OD&D or Holmes bother with Halflings, one would hope that maybe the "regular" movement (of 12" or 120') for player characters might be called for?

Kobolds are apparently under the influence of a Haste spell for Holmes, everybody else agreed that they are too short to move fast? Orcs, on the other hand, are given Formula-1 treatment only by B/X. Skeletons and Treants get the Haste spell by Gary Gygax himself in AD&D. The slow Trolls in Chainmail might be forgivable because there the category is actually "Trolls, Ogres" for whatever reason. Finally my favorite pet-peeve: Zombies, described as particularly slow in all editions that have them, suddenly run circles around everybody else in Holmes and B/X.

Looking at this, I find it difficult to determine who was smoking what when they put the monsters for their game together. Slowing down Halflings to somewhere between Elves and Dwarves? Maybe. Speeding up Skeletons and Zombies? What? Am I the only person in the world for whom "Zombie" always meant "Romero Zombie" while Ghoul was closer to "28 Days Later Zombie"? Maybe the size of a Treant (long legs) justifies giving them the same movement rate that Giants (almost) consistently get? But what about Tolkien's take on Ents and their rather slow habits?

I didn't spend the time to check what more recent retro-clones do with these movement rates. Well, I briefly checked on Delving Deeper and found that Simon has a much more rational set of movement rates. But I do wonder how many have copied "Zombie 120'/turn" without thinking twice about it...

Anyone else want to share their pet-peeves about movement rates?

Update 2014/11/23: Alright, I couldn't contain my curiousity so I checked a few retro clones regarding these monsters. Here's what I found:


Fascinating, isn't it? Delving Deeper's slightly faster Dwarves I can get behind, but that might be because I play a dwarf in my weekly game and I hate that without my boots of flying almost every monster can run away from my axe. Swords & Wizardry once again forgets Halflings in the monster section (just like Holmes), but at least everybody else seems to agree on their movement rate. But aside from Kobolds and Trolls, the remaining monsters are all over the place again, nobody can agree. And Labyrinth Lord is officially the least "thoughtful" clone because Dan copied both the fast movement and the slow description, just like predicted...