Behind the DM Screen – Managing numbers

Alex Schroeder (of campaignwiki.org) and I were having a lovely chat on Mastodon this morning:

   @kensanata: The one thing that surprises me the most in role-playing games: how almost nobody can remember the armour class of the opponent they are fighting when it’s their turn to attack.

   @chgowiz: @kensanata I must be an outlier, I don’t give the AC of the opponent. With Target20, I just have them roll to hit, and give me any modifiers that they know of, such as level modifier or anything that might be relevant to them.

  @kensanata: @chgowiz I think if I juggle more numbers behind the screen it’s going to slow the game down. That isn’t a problem for you?

I started to write an answer, but I realized this was actually a good blog post topic. Or at least I thought it might be…

I’ve been using Target20 for 15 years or so now, so it has become second nature to me. I know the AC of the monster. I see the roll that the player has made. They tell me (or I look at my player cheat sheet) what their level bonus is. I add the three numbers. If they’re 20 or higher, they hit!

Now there are nuances to that, there are other bonuses and penalties, depending on the system I’m running, but in a nutshell, that’s it. Addition is extremely easy, and after doing it a few games, it becomes second nature.

I mentioned a cheat sheet, and it’s something I’ve been doing since 2008. Here’s a picture of it.

Nothing fancy, but for me, it’s how I manage the Target20 info that I need to know. If I’m rolling as a monster, I use their HD as the level bonus, I have the players’ ACs right there and the roll of the d20 – add ’em up and that’s it.

To be sure, there are penalties and bonuses that might come into play – charging bonus, cover/concealment adjustments to AC, magic item effects, spell effects, and so on. The players are very good at reminding me of those, once they learn it’s OK to remind me! And, to be honest, sometimes I forget that monsters have bonuses, so I might give the players a bit of benefit there… but it all evens out in the end.

I’ve also made this easier on me in how I make keys and how I’ve come to think about hp. For my keys, I’ve used a standard stat block … and I’m going to reveal how I “cheat” on hp!

Example, an ogre’s stat block looks like this in my key: (HD:4+1 AC:5 Mv:9 dmg:1d10 M75)

That’s all I need to adjudicate combat. (I should mention that this is output from Alex’s HexDescribe, which helped me to standardize my keys immensely!) The M75 refers to the fact that additional ogre info can be found in the Monster Manual pg 75. There’s the AC for me to know if the players hit. I should mention that I don’t tell the players what the AC is. It might change! They’ll figure out soon enough what dice rolls seem to hit and which don’t…

My cheat on hit points? I never generate it prior, unless it’s a recurring NPC or major monster. I do it at the table, without dice. How?

For OD&D, hit points are generated with d6. Mean of d6 is 3.5 I round up to 4. 2HD would be 7hp (3.5+3.5). At game time, I may tweak that for a challenge, or based on what I think the difficulty of these particular monsters should be. But on average, I mostly use the 1HD = 4, 2HD = 7. The math in my head goes pretty quickly.

For AD&D, since monsters are all usually d8s, it’s a very similar approach! Mean of d8 is 4.5, so I take a similar approach. 1HD = 5, 2HD = 9.

The numbers flow very fast for me now. A 7HD creature in OD&D? 25 hp. I did that in about 2 seconds. (3 * 7 = 21 + 4). I think the bottom line was that I found systems that make the numbers simple for me. This is what I landed on – Target20 and using mean + my game-time-referee-decision for hit points. It means less prep and with time/experience and the organization of my notes and cheat sheets, I’ve tweaked this to what works for me.

So that’s it… why I don’t give out the AC because I’ve simplified what the players need to worry about… what they rolled and what their level bonus is!

What do you think?