I did a lot over the Labor Day weekend. I didn't have much time to write. However, I kept battling a preoccupation with NWP and Skills in Andras. Having a roll-under d20 mechanic meant inventing an arbitrary starting point. I didn't want NWP and Skills to start with high scores because there was nowhere to go.

I had this vision of a Mage having a 17 Spellcraft at 2nd level. The problem? A 2nd level Mage being able to identify a large number of spells when he/she has two in their personal spell book. Over time, this Mage can only gain two more ranks in Spellcraft.

I could assign a lot of modifiers, but I don't want to make a modifier table for every NWP and Skill if I can help it. I could return to the slot-purchase method that is more true to 2e.

I briefly considered a roll-over mechanic and setting DC scores. But I do not want a d20 or 3e mechanic if I can help it. Nothing wrong with it, but the feel changes from something almost like 2e into something very much like 3e.

Looking at some things in my collection, I found a 2d12 roll-under mechanic. It is a great system, but alas, not OGL or Creative Commons.

Then it hit me on Sunday, but I didn't have a chance to write it down until now. I kept mulling a d20+d10 roll-under mechanic. It feels less like 2e, but doesn't feel like 3e. Will I keep it? I don't know yet.

Here's some math behind a d20+d10 mechanic:

  • There are 200 different die rolls.
  • The bell curve is actually a long plateau.
  • Using ability scores, even an 18 ability score only gives you a 62.5 percent chance of success.
Roll Roll <=
2 0.50%
3 1.50%
4 3.00%
5 5.00%
6 7.50%
7 10.50%
8 14.00%
9 18.00%
10 22.50%
11 27.50%
12 32.50%
13 37.50%
14 42.50%
15 47.50%
16 52.50%
17 57.50%
18 62.50%
19 67.50%
20 72.50%
21 77.50%
22 82.00%
23 86.00%
24 89.50%
25 92.50%
26 95.00%
27 97.00%
28 98.50%
29 99.50%
30 100.00%

In thinking about Theives' Skills, this mechanic allows me to set Climb Walls at DEX for a 1st level character. In 2e, the character starts with a 60% chance of success and can increase that ability up to 90% at first level. Starting with DEX and allowing a character to go up 6 ranks only does the same thing if the Rogue has an 18 DEX. I like that a lot. Speaking of Theives' Skills, d20+d10 also allows me to set values very close to OSRIC percentages for success for NPCs.

This mechanic also enhances my ongoing struggle with creating a skill-based Mage. The skill to cast a spell starts with INT and increases by INT Bonus at every level. So, for an INT 16 Arcanist, they begin with a Spellcasting Skill of 16 and increase by 2 at every level.

In doing the numbers, this also simplifies the modifiers based on spell level. An Arcanist casting a 1st level spell has no modifier. A 2nd level spell has a -5 modifier to Spellcasting Skill. A 3rd level spell is -10 and so on. So much simpler! In looking at creating spells using the OpenD6 system, it is also possible to create 0 level spells. They would have a +5 bonus to Spellcasting skill.

With 0 level spells, this mechanic also allows for a little bit of house magic by NPCs. Assuming an INT of 12, an NPC would have a better than 50/50 chance of casting a 0th level spell. Considering the minimal effect, this is enough to make things interesting without severe unbalancing.

The effects of 0th level spells would include things like divining one answer to a yes/no question, fists do 1d3 lethal damage for one round, divining the last image seen before death from a fresh corpse, a oen time +3 skill bonus for one usage of a Thief skill, etc. All of these effects are dependent on a lengthy casting time and verbal, somatic and material components. Without these four things, the effects are more comparable to 1st and 2nd level spells.

Lots of options are still available, but it's food for thought. You have any thoughts?