Spell Failure in Blackmoor

Author: DHBoggs /

Magic in early Blackmoor has often attracted interest, in part because it appears to have been so different from the "Vancian" system Gygax adopted for D&D.  When Arneson developed the magical component of his Blackmoor campaign he had little to go on in terms of source material.  The first edition CHAINMAIL booklet did list a handful of battlefield spells, but not much else.

In his write up in the FFC titled "Original Blackmoor Magic", Arenson supplies a good general description of the methods he devised, but few of the specific details the curious gamer might wish for.  However, by pulling in information from other Blackmoor sources, we can cobble together a more complete picture.

In particular, one aspect that has drawn some attention and has attracted a number of fans over the years is the idea of spell failure.

Arneson wrote: "...there was always a chance of failure in spells (unless they were practiced)"  FFC77:74

Presumably "they" means the spells, though it could mean the wizard, which might be more sensible, since it is unlikely Arneson or anyone else would want to keep track of how many times a wizard cast a particular spell in order to maintain some threshold of being "practised" with it.  Given that Arneson also tells us "...to progress to a new level, one first learned the spells... there was no automatic progression, rather it was a slow step by step, spell by spell progression." FFC77:74, we can read that to mean mastering a spell level to the point of no failure meant you were "practised" with those spells.

We know from other sources - the Corner of the Table Newsletter in particular - that wizards also had "levels".  The highest level we know of being 12, in the case of a 12th level sorceress mentioned in the after action report of the July 1972 battle of Lake Gloomin.

We also know that spell failure varied among casters.  The description of the Gin of Salik tells us "His magic spells are among the most potent in the world with no chance of them failing..." FFC77:20

For the 7th level Ran of Ah Foo: "He also has a spell workshop that turns out one Level I spell a week and one Level II spell a month with one level III spell a year.  These are portable but not reusable with only a 15% failure rate."  FFC77:19

And finally, the bumbling Egg of Coot, who sells spells with a "30% chance of failure per level of spell, i.e. III = 50%, II = 40%, etc."  FFC77:18

A last bit of information to consider is the number of spell levels themselves.  The highest spell level appears to be level IV, because of the Gin's spells we are told. "All of which are level IV, at a rate of one every two months..." FFC77:20

Thus we have some numbers to play around with here.  Correlation does not equal causation, but the above certainly suggest, as we might expect, that as a wizard advanced in level their rate of failure declined, so let's go with that and see where it leads.  We can start with the Egg and assume he (or whoever makes his spells) is a Wizard of unknown level producing spells of levels I through IV.

The failure pattern at this level x is:

Spell level I,  30%
Spell level II  40%
Spell level III 50%
Spell level IV 60%

If the Ran is really level 7 and has a 15% fail rate, the the pattern above would seem to change in 5% increments.  The text implies all of his spells fail at 15%, so perhaps there is a change of the rules between these two examples, but if we presume this rate applies to Ran's best spells (level 3), we get this:  

Spell level I,  5%
Spell level II  10%
Spell level III 15%
Spell level IV 20%

However, if we go back to the Eggs failure rate, and improve in 5% increments from the worst it could represent (1st level wizard), we get a table like this:


Wizard Level
I Spell
II Spell
III Spell
IV Spell
1
30
40
50
60
2
25
35
45
55
3
20
30
40
50
4
15
25
35
45
5

20
30
40
6

15
25
35
7


20
30
8


15
25
9



20
10



15
11



10
12



5

We're told the Ran is 7th level but the 5% table based on the Egg's failure rate tells us that a 7th level wizard should have a 20% failure rate at level 7 and a 15% failure rate at level 8.  So either the Ran is 5% better than he should be, or the Egg is 5% worse.  The latter seems a lot more plausible.  So let's recast the table assuming Ran has a "standard" failure rate.


Wizard Level
I Spell
II Spell
III Spell
IV Spell
1
25
35
45
55
2
20
30
40
50
3
15
25
35
45
4
10
20
30
40
5
5
15
25
35
6
0
10
20
30
7
0
5
15
25
8
0
0
10
20
9
0
0
5
15
10
0
0
0
10
11
0
0
0
5
12
0
0
0
0

There's a couple more reasons to prefer this second table, first, because it benefits players slightly, and secondly because it zero's out at level 12, which is the highest level we know of as mentioned earlier, and we know in at least the case of the Gin of Salik, it is possible to be at a level so high your spells do not fail.

To apply this table to D&D spells, the Referee should change only the range of spell level, and I would recommend that only for the last 2 columns so that "III spell" becomes Spell level 3 &4, and IV Spell becomes spell levels 5 & 6.

What exactly happens when a spell fails is up to you.

10 comments:

gmkeros said...

I was just skimming through that and a thought came to me: why not have a spell failure happen when a creature manages to succeed in the spell save? Instead of nothing happening the magical powers might get out of hand and create weird effects

DHBoggs said...

Yeah, could work for creatures that get a save, but there are, of course, a lot of spells being cast that aren't targeting powerful monsters, so you would still need a fail roll for that.

GameDaddy said...

Interesting! In our gaming group we had several different things we tried over the first couple of years. My original GM was in college at CSU in Ft. Collins. He was also in the ROTC (where he had learned about D&D, we had been playing wargames before he even went to college). Anyway he would always be home for a few weeks at Christmas, and over summer vacation, and that was literally the only time I got to play D&D and wargames with someone more experienced than me. So really it was up to us, to figure out how to apply the rules to play the game, and GM got to decide for his, or her game. By 1980 I had girls in my gaming group, who were creating their own fantasy worlds and GMing.

Anyway before 1978 was finished, I had acquired a copy of Greyhawk, as well as Blackmoor, and the copy of Greyhawk had the details for the chance to know any given spell… and it was based on the Intelligence of the magic-user.

Intelligence % chance to know Minimum # Maximum #
of MU an\ given spell per Level* per Level*
3-4 20% 2 3
5-7 30% 2 4
8-9 40% 3 5
10-12 50% 4 6
13-14 65% 5 8
15-16 75% 6 10
17 85% 7 all
18 95% 8 all

Now the Wizard’s in the game had to keep a spellbook to study to relearn their spells, and when they leveled, as a GM I let them pick spells off the list they wanted to be able to cast, but they would have to roll for that %chance to know the spell.

So, for example, My Player Shane, rolling up a 1st level Wizard with say, an Intelligence of 15. His Wizard began knowing a minimum of six spells (which would be in his spell book), and he would be able to know up to ten spells of the 1st level. I would let the Shane roll randomly for the spells he started with. If Shane wanted to start with light and magic missile I would let him roll, and he had a basic 75% chance of knowing the spells so…

GameDaddy said...

...88 no on the light spell
...93 no on the magic missile spell
next he picked Read Magic and Hold Portal
17… yes on the Read Magic
32… yes on the Hold Portal
next Shane picked and rolled for Charm Person, and Sleep.
09… yes on the Charm Person
95… no on the Sleep spell
next he picks to study Protection from Evil, and Read Languages
76… no on the protection from evil
24… yes on the read Languages
next he picked Shield and Detect magic off the list…
19… yes on the Shield
82… No on the Detect Magic
last 1st level spell on the Greyhawk list was Ventriliquism, so Shane rolled for that…
a 12, so yes on Ventriliqism… His starting spell book looked like this:

1st Level Spellbook
Read Magic
Hold Portal
Charm Person
Read Languages
Shield
Ventriliquism

And Shane could pick one spell a day in the morning to study to be able to cast. Now when Shane’s Wizard character leveled, he received another chance to roll for the 1st level spells he had missed out when first acquiring his spell book, up to the maximum spells allowed per level based on his Intelligence. Eventually their was a high likelihood of the Player having all of the spells he wanted, however it was never a guaranteed thing, magic being unpredictable as it is...

Now we added the chance of casting failure to Magic Spells very early on with a house rule, and it worked like this, whenever a Wizard cast a spell, he had to make a percentile roll equal to less than 5x his intelligence, or a d20 roll equal to, or less than his Intelligence, in order to successfully cast the spell. If he didn’t make the roll, he didn’t remember the verbal or somatic components of the spell correctly, and the spell was miscast. If he rolled a 20 or 100% on his spellcasting roll it was a critical fail and the spell backfired affecting the caster instead the target.

Later on shortly after AD&D came out we added another house rule to our basic D&D games, so that players could wear armor and use swords and such, and also cast spells. Wearing armor reduced the chance of casting a spell by (10 minus the armor class * 5%) so wearing no armor at all, would not affect the spell in any way. Wearing leather (AC:8) reduced the casters chance of success by 10%, So Shane, wearing leather armor, only had a 65% chance of successfully casting his spell (of any spell level). If Shane was wearing Chainmail AC:6 his chance of casting the spell was only 55%, and if Shane’s Wizard was wearing full Platemail AC:3 his chance of successfully casting his spell was only 40%. Not a fail, but certainly not good odds. Likewise each heavy weapon the Wizard carried like a longsword or axe, decreased his chance of successfully casting a spell by an additional 5% for each weapon the Wizard carried.

Later on, buying Warlock, and of course, Arduin, we had these new critical spell failure tables that we delightfully added into our games… Wizard’s in our D&D games were never the all powerful class that they had the bad reputation for from AD&D.

Snowgen said...

Have you looked at Empire of the Petal Throne? Remember that Professor Barker was in the Twin Cities and thus E.P.T. is more Arnesonian than Gygaxian.

Anyway, section 434 of E.P.T. is "Regeneration of Spells and Likelihood of Their Working". In short:

Level I: 60% chance that spells Will NOT work
Level II: 50%
Level III: 40%
Level IV: 30%
Level V: 20%
Level VI: 15%
Level VII: 10%
Level VIII: 5%
Level 9 and up 0%

However this is modified by the character's Psychic Ability. Characters that are "Quite Psychic" (81-95) have a +15% chance that the spell works, while "Highly Psychic" (96-100) characters have a +25% chance that the spell works.

Hope this helps!

Sebastian DM said...

Interesting read! Do you know any references about how often magic users could expect to be able to cast spells? I remember them using super berries as a kind of fuel for spells, but also that one of them had his own tree where he could pick them from. So I guess it might have been limited to how many of these berries could be carried around or somethingm

DHBoggs said...

GameDaddy - very cool. thanks for sharing that. I particularly liked the armor rule.

>>>"Now when Shane’s Wizard character leveled, he received another chance to roll for the 1st level spells he had missed out when first acquiring his spell book, up to the maximum spells allowed per level based on his Intelligence."

The chance to reroll each level is an interesting twist. I like it. It sounded like you replaced the "vancian spell slot" method for the number of spells an MU has with the chance to know list (an intriguing idea) or did you use both together as I'm sure most people would have done?

DHBoggs said...

Snowgen -Thanks for posting that. I hadn't looked at EPT's spell failure rules in a long while. Interesting how the numbers line up with the Egg of Coot's. Barker's rules certainly do reflect a Twin Cities style.

If you like things EPT (and who doesn't) you might find Humanspace Empires intersting. Have a look here https://boggswood.blogspot.com/2016/05/new-humanspace-empires-free-pulp-sci-fi.html

DHBoggs said...

Sebastian -
Righto. According to Arneson in the FFC, casting was only limited by your supply of ready made spells and scrolls, however he did employ some sort of magical exhaustion rule involving characters' constitution (health). There are also magical exhuastion rules in Adventures in Fantasy, but they are grounded in that system and not easily translated to D&D.

GameDaddy said...

Well, once the Mage knew the spell, he/she simply had to rememorize the spell every day by reading his/her spellbok, and the mage could memorize up to the listed spell limit per day, and then cast at will provided the mage had the spell components and could exercise the verbal and somatic components of the spell. Originally I had them frequently roleplay their casting for the benefit of the other party members.

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