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, August 08, 2022

Quick d20 skills thought: trying again, critical failures and climbing

 After a quick d6 detour, let's go back to 1d20 skills.

As we've seem, climbing is a bit odd, because of the big chances of success from level 1. The motive is probably a practical one: the consequences of failure are dire. From the OSE SRD:
A roll is required for each 100’ to be climbed. If the roll fails, the thief falls at the halfway point, suffering falling damage.
So, to climb one kilometer, you have ten attempts, and you'll probably die. Those "good" probabilities are not looking so good right now.

And if you make it 1d20+level... things get even worse.


Consider one alternative. Say, 1d20+level, try to get 20. This means 10% chance of success on level 1. BUT. Failure means you're STUCK. A natural 1 means you fall.

And you can try again. Multiple times. But if you roll a 1...

(This works well for dangerous skills, but I usually DO NOT like critical failures when fighting. Except, maybe, for a particularly dangerous maneuver).

Have you ever tried rock climbing? If there is no way to continue, you can usually just climb back. Falling doesn't happen so often (but, when it does, it can be deadly).

Another thing to consider: if you're climbing a mountain, you're not looking for the most vertical wall to climb (unless you're doing it for sport)... probably the opposite. If you fall, you are unlikely to fall ALL THE WAY down. Maybe there is some chance you'll fall to a lower point. Say, a 100' fall (or, even better, 1d20x10'). Which will kill most characters, but not all.

This works well for climbing. But is also a great system for thief skills in general: try multiple times, but a natural 1 means disaster. Looking or disarming traps? Guess what, the trap got to you first. Lockpicking? You broke your set of picks. Hearing noise? You're pretty sure you didn't hear anything, and if there IS someone there, he heard you instead! Reading magic scrolls? The system works perfectly!

This "solves" thieves' skills in two ways: it makes them more effective (multiple attempts) while making disastrous failure less likely (only 5%... at first).

If you want to add tension (and agency), you can always offer your players a hard choice after they fail two or three times. It works with climbing, but also traps, lockpicking, and so on.

"Okay, there is nowhere to hold your hands... except if you jump a few feet to the die. You need 10 or more to succeed, but if you fail, you fall... What do you do?"


  1. I prefer the %-based skills but use a similar system - multiple attempts, but fail on doubles and something bad happens.

    1. Nice! "Fail on doubles" is even better than 1-in-20 because the chances of disastrous failure are smaller as you get better at climbing.

  2. There are some interesting things that can be done with this system, for a modest increase in complexity. For instance, you can increase the chance of critical failure for each subsequent attempt at something, possibly while also decreasing the target number for success; e.g. the more you try, the more likely you are to finally succeed, but the danger also increases. Do you take another crack at it, or accept failure and move on...?

    1. Good idea! That would be interesting - an "escalation" of sorts. Would be nice to avoid trying the same things half a dozen times.