RPGaDay2019 Day 9 – Critical

For day 9 of #RPGaDay2019 we get critical, following Obscure yesterday.

When I started with BECMI, there was no concept of critical rolls – no critical success or critical failure. My friends played AD&D, so I’d hear them talking about a critical hit and wonder what this was.

Fast-forward 35 years to 5e. It’s there in the PHB (p194).

Rolling 1 or 20

Sometimes fate blesses or curses a combatant, causing the novice to hit and the veteran to miss.

If the d20 roll for any attack is a 20, the attack hits regardless of any modifiers or the target’s AC. This is called a critical hit – see later.

If the d20 roll for an attach is a 1, the attack misses regardless of any modifiers or the target’s AC.


Critical Hits

When you scare a critical hit, you get to roll extra dice for he attacks’ damage against the target. Roll all of the attack’s damage dice twice and add them together. Then add any relevant modifiers as normal.

Looking at this, we did actually have most of it. See my comparison post from a few days ago. Certainly a natural 1 always missed regardless of how experienced you were. On the upper end, it wasn’t quite the same. A 20 only extended across 5 ACs, and then you needed modifiers to hit better armour classes than that. And there wasn’t the concept of additional damage on a natural 20.

It does make for additional excitement. If you have half a dozen characters, there is a roughly 50% chance that someone will roll either a 1 or a 20 on each round (47%) and roughly a 1 in 4 chance that someone will roll a 20 (27%). So it is likely there will be a critical hit at least once in a battle – and whoever gets it feels awesome.

However, it seems “everyone knows” that a 20 is a critical hit with extra damage, and a 1 is a critical fumble – not just a miss, but something actively going wrong, like dropping the weapon, or hitting an ally. Also “everyone knows” that it applies to any d20 roll including a saving throw or a skill check. Note there is nothing about these in the rules…

This can lead to fun. I had a situation where a character rolled a 1 on an attack, so I ruled his sword went flying out of his hand straight towards another character, and asked him to make a dexterity saving throw. He rolled a 20, so I said he had actually managed to catch the sword rather than just dodge it.

However, it can also encourage (along with a misunderstanding of how effective skills can be) the sort of thing my son got caught with by another player in one of the first sessions he ran. The player stated their character was trying to chat up the barmaid and said “so I roll a Persuasion check – 20 so she comes with me and does what I say. I take her outside and I stab her to death. She is surprised because I rolled that 20 in Persuasion”. Of course there’s more wrong here than the assumption that a 20 is a critical success. It’s not up to the player to decide whether they make a skill check, and even if the GM asks them to make the check, it’s not like a charm person where you can make someone do whatever you want. However, the assumption of critical success applying to a skill check is definitely a major contributor to that unrealistic override of the GM.

I wonder where the whole concept of critical success comes from. I have just checked back in my old AD&D manuals, and I find it uses a very similar progression to BECMI. As Gary says:

A quick glance at the progression of numbers on the COMBAT TABLES will reveal that 20 is repeated. This reflects the fact that a 20 indicates a “perfect” hit. It also incidentally helps to assure that opponents with high armor class value are not “hit proof” in most cases.

Gary Gygax, AD&D DMG from 1979, 9th printing 1987, p82

Although he does have certain failure on saving throws on a 1, certain success on 20 is only a suggestion:

Certain failure: As shown on the table, a 1 is ALWAYS a failure, regardless of magical modifiers to the contrary. … Another rule you may wish to consider is allowing a save (where applicable) on a natural 20, regardless of penalties.

Gary Gygax, AD&D DMG from 1979, 9th printing 1987, p81

Interestingly these rules explicitly exclude double damage:

… With complex combat systems which stress so-called realism … either this option is severely limited or the rules are highly slanted towards favoring the player characters at the expense of their opponents. (Such rules as double damage and critical hits must cut both ways – in which case the life expectancy of player characters will be shortened considerably – or the monsters are being grossly misrepresented and unfairly treated by the system. I am certain you can think of many other such rules.)

Gary Gygax, AD&D DMG from 1979, 9th printing 1987, p61

What I find particularly interesting about this is that the concept of double damage and critical hits is obviously out there at the time he wrote these rules because he feels the need to state them to exclude them. So I wonder where they come from, and why they are so foremost in everyone’s awareness as “applying to any d20 roll” (even The Angry GM feels the need to refute this concept, so is clearly aware of it).

I have to say, while critical failures were interesting to start with, the novelty is starting to pall. I’m running out of interesting ways attacks can fail catastrophically. I think I will stick to:

  • natural 1 always fails, regardless of modifiers
  • natural 20 always succeeds, regardless of modifiers (not completely sure of this – if there is a really high DC, I might decide to require modifiers on top of a natural 20)
  • a natural 20 on an attack (only) additionally causes a critical hit, which does double the damage dice

Tomorrow we have “Focus”.

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