"Black Dougal gasps 'Poison!' and falls to the floor. He looks dead."

Monday, April 5, 2010

B/X Skills, Actions and Resolution Subsystems

A quick read of the B/X rulebooks gives a list of the following resolution systems (and I may have missed some):

1. "to hit" rolls
2. saving throws
3. thieves' abilities
4. turning undead
5. opening stuck doors
6. finding secret doors
7. listening
8. reaction rolls
9. surprise
10. damage
11. morale
12. ability checks (save vs abilities)
13. evasion
14. foraging
15. spell research and magic item creation
16. becoming lost

These can be broken down into the following basic mechanic systems:
d20 vs target number
1d6, 1 or 2 succeeds
2d6 higher better
d20 under target number
d% vs target number

I think they can also be broken into the following thematic groupings:
"to hit" rolls - combat actions and maneuvers
saving throws - last ditch reaction to an action
reaction rolls - social, non-combat interaction
morale - combat interaction
open doors, foraging, etc - proactive, non-combat, physical, adventuring-type actions
find secret doors, listening and surprise - perception, awareness, intuition, etc.
ability checks - proactive skill-based actions
d% - very granular skills and "holy crap" actions

A quick look at the d20 SRD lists the skills below. Based on the B/X resolution systems, I have given a quick "conversion" of how I would handle each d20 skill-based action using B/X. Of course, each situation may be different and how I may handle each situation may change based on various factors.

Appraise - either roll a 1 or 2 on a d6 or an ability check
Balance - either a dex check or a d% check, maybe a "to hit" roll modified by dex if in combat
Bluff - reaction roll if outside of combat or a morale check if in combat
Climb - a thief ability, dex check or a d6 roll
Concentration - I wouldn't use this
Craft - either an ability check or a d6 roll
Decipher Script - read magic or read language spells, maybe a Int check of a d6 roll
Diplomacy - reaction roll
Disable Device - thief ability
Disguise - a d6 roll or a d%
Escape Artist - a d6 roll or a d%
Forgery - a d6 roll or a d%
Gather Information - reaction roll or a d6
Handle Animal - reaction roll
Heal - healing rules are given in the rulebooks
Hide - thief ability or surprise roll
Intimidate - reaction roll if outside of combat or a morale check if in combat
Jump - d6 roll, a dex check or maybe a d%
Knowledge - d6 roll or an int check
Listen - d6 roll
Move Silently - thief ability, surprise roll
Open Lock - thief ability
Perform - reaction roll
Profession - ability check or d6 roll
Ride - I assume everyone know how to generally ride a horse. Actions that may cause a rider to fall off or lose control of the horse are reactions to other actions so I would give a saving throw.
Search - find secret doors
Sense Motive - the players can decide if the trust someone
Sleight Of Hand - a thief's pick pockets or maybe a dex check
Speak Language - either they know it or they don't
Spellcraft - maybe give a magic-user a chance
Spot - listen or find secret doors
Survival - forage or becoming lost check
Swim - given on page X51
Tumble - maybe a dex check?
Use Magic Device - just use the rules as given in the rulebooks
Use Rope - a d6 roll

EDIT: One thing this shows me is that you can do everything that a skill system can do just using the B/X rules.


  1. Ah, Easter monday.

    I'd be tempted to just let the players' actions succeed, unless they are trying an action that is clearly too difficult, based on their class or level.

    For example, I might reason that low value gems can be accurately appraised by 1-2nd level thieves, mid-value gems and low value jewelry by 3-4th level thieves, and so on.

    The problem I see with converting to die-rolls, is facing the same challenge you discuss in your earlier post "But I Rolled It!"

    As an alternative, someone recently posted about using ability-score checks, using 2d6 for easy tasks, 3d6 for difficult tasks, and 4d6 (or more) for impossible tasks. That might be another way to employ skill checks.

  2. In a lot of cases I do go for a "Say Yes" approach.

    I do like the fact that the simple B/X system can handle everything that d20 can do and often in a much easier fashion.

    A testament to rules-lite, old school D&D.

  3. On all those points, we are in full agreement!

  4. @Paladin - Mentzer had the xD6 and d20 with mods vs. Ability score in the basic set DM book as an optional rule more than 25 years ago...that 'recent post' isn't so new.

  5. Everything that's old is new again!