I was playing around with the old Mentzer Monster Reaction Chart yesterday. I was mapping the 2d6 results to other types of dice because I was thinking of a way to use it in D&D 5e. I used the website AnyDice to work out the probabilities and the rest was math. Anyhow I kind of tweaked around the numbers and realized I could make a super condensed version. Well okay, super condensed would be Hostile, Neutral, Friendly. I wanted something a bit more complicated than that to preserve some of the things I liked. Anyhow, this one is mapped to an unmodified d20. The intention is to gauge the Monster/NPC's intention or mood on encountering the Player Characters. This would be before things like Charisma and skills come into play.

1: Immediate Attack
2-6: Hostile; 1-14 Attack, 15+ Retreat
7-14 Back Away Slowly and Leave
15-19: Amicable; 1-6 Offer a Pleasant Day and Leave, 7+ Friendly
20: Immediately Friendly

And that's it. Hostile and Amicable get a second roll. I could have added it to Back Away Slowly but I really didn't see much point in adding a redundant nested loop. The most simplified version would like like.

1-6: Attack
7-14: Leave
15-20: Friendly

I might do something a bit more akin to the original nested monstrosity, though I may try and make the redundant less redundant by offering different results. I'm still thinking on that one. The mapping from 2d6 to 1d20 isn't exact, but it's a decent approximation if you prefer to use a d20. The way it maps out is like this.

2 (2.78%) --> 1 (5%)
3-5 (25%) --> 2-6 (25%)
6-8 (44.45%) --> 7-14 (40%)
9-11 (25%)--> 15-19 (25%)
12 (2.78%) --> 20 (5%)

There is no way to map out the dice perfectly but it's good enough for me.

What did you gain by changing from 2d6 to 1d20?

Quote from: Dumarest;961489What did you gain by changing from 2d6 to 1d20?

It's mostly for 5e where 2d6 isn't really a common mechanic which could be adapted to other d20 based games. Hence why I added the third chart with the probabilities so that the original mechanic is preserved. Mostly this was just a fun exercise because I like to play with numbers. If I ever get my OSRish thing written I'll likely use an adaptation which uses 2d6 and keeps to the original.

I was wondering, because I looked at the percentages for each result and it seemed the same, so I thought maybe I missed something.

I use BX/Mentzer 2d6 Reaction & Morale systems in all my games. Can't see any reason not to. Certainly see no reason to convert to a d20 and lose the bell curve when applying modifiers.

Quote from: S'mon;961500I use BX/Mentzer 2d6 Reaction & Morale systems in all my games. Can't see any reason not to. Certainly see no reason to convert to a d20 and lose the bell curve when applying modifiers.

The d20 table is meant to be used without modifiers. It's probably not final, more of a framework that I am making. I'll probably use 2d6 for Approach, though that's hard to say because I accidentally came up with two engines for it.

Quote from: Dumarest;961497I was wondering, because I looked at the percentages for each result and it seemed the same, so I thought maybe I missed something.

Check the ranges. They are deliberately supposed to be close. I also mapped it out to a d24 and d30 to simulate bonuses from Charisma and Skills. Once I work out the d20 end of it, it will probably just be some one page thing. Using 2d6 I may do something closer to the originals. I still have to work out probabilities for the redundant recursions.

I've never noticed that basically 7+ on d20 = no fight (or whatever it was via 2d6, assuming same odds). That's very interesting.

Definitely not something I have ever seen in a game I've played. Monster get fought constantly, with a very occasional talking encounter as something different.

Is there a formal "escape/flee combat" rule in Mentzer? If not, I think I might understand why. This reaction table is kinda a party retreat rule in reverse - the GM can throw any intelligent/communicative NPCs at the party, safe in the knowledge that there's good odds it wont be a fight (unless the party starts one - and if they do, the results are on them).

In later versions of D&D, the reaction table was lost, but no flee rule implemented, which lead to the need for ... "balanced encounters".

Quote from: Psikerlord;961506I've never noticed that basically 7+ on d20 = no fight (or whatever it was via 2d6, assuming same odds). That's very interesting.

There are a lot of very interesting details you notice when you really look at the rules to older D&D or Classic Traveller that really change your perspective on what was expected of a game. For Traveller, there's a guy on here called Christopher Kubasik (spelling may be wrong) who has a blog going over Classic Traveller with a fine-toothed comb and coming up with intriguing revelations. It would be cool if someone was doing that with AD&D or Basic or 1974 D&D. Or maybe someone is already?

Quote from: Dumarest;961508There are a lot of very interesting details you notice when you really look at the rules to older D&D or Classic Traveller that really change your perspective on what was expected of a game. For Traveller, there's a guy on here called Christopher Kubasik (spelling may be wrong) who has a blog going over Classic Traveller with a fine-toothed comb and coming up with intriguing revelations. It would be cool if someone was doing that with AD&D or Basic or 1974 D&D. Or maybe someone is already?

Yeah I think I'm going to have to find a copy and go over it myself, just out of interest

I like BX's system. But 5e's works overall the same. Though I think BX's has the greater leeway for swaying even hostile encounters which makes a passable, or even good CHA useful.

In 5e's system you cant sway reactions so dramatically. Though some might well see that as a strength.

Quote from: Psikerlord;961510Yeah I think I'm going to have to find a copy and go over it myself, just out of interest

Start a thread! I'll read it.

Quote from: Psikerlord;961506Is there a formal "escape/flee combat" rule in Mentzer? If not, I think I might understand why. This reaction table is kinda a party retreat rule in reverse - the GM can throw any intelligent/communicative NPCs at the party, safe in the knowledge that there's good odds it wont be a fight (unless the party starts one - and if they do, the results are on them).

Dont know about BECMI but in BX yes there were rules for surprise and retreat. page B24, Evasion and Pursuit. Makes use of the reaction table to determine of they follow or not. Monsters break off pursuit of the PCs can get out of sight.

The reaction table takes into account the bell curve so undecided reactions are the most common and friendly and hostile ones are rare. If I recall correctly it should be much the same in BECMI as there wasnt as much rules drift between iterations.

Quote from: Omega;961518I like BX's system. But 5e's works overall the same. Though I think BX's has the greater leeway for swaying even hostile encounters which makes a passable, or even good CHA useful.

In 5e's system you cant sway reactions so dramatically. Though some might well see that as a strength.

My main reason for not including modifiers is that I was mostly mapping dice and wanted to work out the base numbers. Plus the OSR thing I am working on uses Approaches (basically broad skills and  expressed as adjectives rather than nouns) to replace skills by associating actions (including saving throws) to each one. I want the game to scale similarly to BECMI/RC so I need to get that down first. But I decided a while back that I wanted to use the Mentzer charts in some way. Using it for 5e is just gravy.

Quote from: Omega;961525Dont know about BECMI but in BX yes there were rules for surprise and retreat. page B24, Evasion and Pursuit. Makes use of the reaction table to determine of they follow or not. Monsters break off pursuit of the PCs can get out of sight.

The reaction table takes into account the bell curve so undecided reactions are the most common and friendly and hostile ones are rare. If I recall correctly it should be much the same in BECMI as there wasnt as much rules drift between iterations.

ooohh the plot thickens! OK I'm gonna have to get my hands on these earlier rules and do a good read thru - thanks Omega!