I must create a system, or be enslaved by another man's. I will not reason and compare: my business is to create.

- William Blake

Monday, September 12, 2022

Minimalist OSR: Target 18?

I talk about Target 20 a lot in this blog. [for this post, I'm assuming you are familiar with Target 20]. I really like it. 

A few weeks ago, someone (might have been John Stater, author of Blood & Treasure* - this game looks awesome!) mentioned to me they used 18 instead of 20. 

And, well, I like this one too.

First, THAC0. Target 18 is a bit off, although target 20 is not perfect either. Doesn't bother me. Fighters and monsters hit more often if you're using descending AC and this system, which is nice. But, overall, I prefer ascending AC these days, so this is not a primary concern.

Now, thief skills. Again, target 20 works well, but target 18 gives the 1st level thief 20% chance with this system. It is closer to the original values, and thieves deserve a boost.

Same for saves. If you're using a single save, which I prefer, 18 is closer to the original numbers. And anything much lower makes it too easy if you're adding your whole level to saves, as Target 20 does.

Finally, 18 is, by itself, a 15% chance. And this is almost the same as 1-in-6 chances. You can use this as an universal mechanic to do anything for PCs that have no skills.

Anyway, here is what I am using for OSR minimalist system. You should check it out - there is a draft in my public folder.

To do anything, roll 1d20, add your ability score modifier plus other modifiers (e.g., from class or race), with 18 or more signifying success. A “challenging” difficulty is assumed; the GM may set other difficulty number (DC) for particularly easy or hard task, as indicated in the table below.

Notice that a DC of 18 is similar to 1-in-6 chances or 15% chance, making it easy to convert tasks from other systems to this one (e.g., if you have 3-in-6 chances of getting lost, avoiding it is an “easy” check). 4-in-6 would be closer to DC 7 but I like the 6-10-14-18 progression. Maybe I change it to 4-7-10-14-18 to fit the x-in-6 pattern...

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  1. I really like what you're doing here Eric. One question though: there's quite a lot of "No chance" dashes on the chart. What kind of bonuses is a PC going to have to have ever to roll a 40? It's this area that using multiple dice are useful as in T&T where you can use an exploding dice mechanism.

    1. Thanks! Yeah, getting 40 is impossible in most games. I left it there because I'm thinking of a system going all the way from level 1 to 20, with an identical bonus (e.g., a 17th-level thief has +17 to sneak around, plus Dex modifier).

      Overall, the idea is not setting harder and harder DCs, but sticking to 18 in most cases.

      With that said... I like ideas that let you go "beyond the max", like exploding die, etc. I might let a d20 "explode" somehow to reach a DC over your max. Maybe a natural 20 allows you to roll again with a cumulative +10 bonus and take the best result.

    2. Well, if you 'free up' the natural 20 by having an 18 target system, you could use it as an exploding die I guess.

  2. Very nice idea and it made me want to work further on this. I added it to a personal list of mine in here: https://alchemistnocturne.blogspot.com/2021/11/greatest-hits.html

  3. Just to make sure I am reading this right, you would then have 'save penalties' translate to a DC increase?

    Thinking of Basic D&D '-4 to X save' roll

    1. Well, you could use them as written or change the DC (although I cannot remember any specific cases in B/X, except, I think, the vampire).