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Monday, July 2, 2012

Spell Study Series: Detect Magic/Hold Portal

I want to do a series of posts on D&D spells, one to three spells at a time. This is partly preparation for Liber Zero, but also an opportunity to explore implied rules in the original game, as well as a chance to think about possible rulings I'd make or have made for each spell. This will tie into other conclusions I've made about the original spell system, such as the original spell-by-spell breakdown (six parts linked in this follow-up post.) However, I'm expecting to change my mind on several of my previous interpretations.
I'm starting with the first two spells:
Detect Magic: A spell to determine if there has been some enchantment laid on a person, place or thing. It has a limited range and short duration. It is useful, for example, to discover if some item is magical, a door has been "held" or "wizard locked", etc.

Hold Portal: A spell to hold a door, gate or the like. It is similar to a locking spell (see below) but it is not permanent. Roll two dice to determine the duration of the spell in turns. Dispell Magic (see below) will immediately negate it, a strong anti-magical creature will shatter it and a Knock (see below) will open it.
I'm grouping these together not only because they are the first two spells listed, but because Detect Magic specifically refers to Hold Portal. There's a certain implication here: without Detect Magic, you are unable to tell if a door is magically held or merely locked, barred or stuck through quick observation. Sure, if there's light on the other side of the door and you peer through the crack, you might see the shadow of a timber barring the door, but the point is: if a door doesn't open on single quick yank, you have to make a decision whether to waste time on a magically-held door.

Hold Portal seems specifically intended to slow down pursuing monsters without permanently sealing an exit or having to take time to spike the door. It will stop pursuit for at least 2 turns (combat turns of 1 minute are probably intended here,) and on the average it will last about 7 turns. There are a few other conceivable uses, like temporarily sealing a trap door that dumps material into a room, but it's a pretty simple spell compared to the Wizard Lock we'll be looking at later.

Range and duration aren't specified for Detect Magic, other than as being "limited and short". I think this should be the default duration for most detection spells: you can detect one thing (magical/not-magical) immediately. There will be exceptions later on (Detect Invisible and Infravision, for example,) but these exception fit with the implied needs of those spells.

Default range for both Detect Magic and Hold Portal, on the other hand, could be linked to spell level; 10 feet per spell level seems like a reasonable range. This is in contrast to some hypothetical ranges I've given in other posts, but I'm thinking of exploring a switch to this for at least one type of spell. As this series progresses, I'll have a better idea how this would work.


  1. Hold Portal is definitely meant to emulate whatever spell it was Gandalf cast in Moria.

    1. Perhaps, but I don't want to get bogged down in fictional or legendary sources; I want to focus on what the text of each spell suggests as far as range/duration patterns and implied setting details, with an eye towards simplifying the spell system.

  2. Hold Portal is definitely meant to emulate whatever spell it was Gandalf cast in Moria.

  3. How do you handle initial first level spells for magic-users? Do you start everyone with "the" book of first level spells, as seems to be implied by Men & Magic?

    Characters who employ spells are assumed to acquire books containing the spells they can use, one book for each level.

    Greyhawk expands the meaning of intelligence to include minimum and maximum spells and % chance to know spell, which I suppose can also serve as guidelines, but have never seemed very satisfactory to me.

    1. Back in 1980, when I was led astray by AD&D, we used the by-the-book method, which is close to the Greyhawk method. I don't remember having any negative feelings at the time, but since then, I've come to dislike the Greyhawk approach, for a number of reasons I'll probably address in a separate post.

      When I was running OD&D earlier this year, we used Men & Magic by-the-book: all first level M-U PCs begin with the eight 1st level spells listed; any other spells, including other 1st level spells, must be researched. I like this because it gives M-Us a strong reason to adventure.

      What I may do in the future is use a selection method I've posted about previously: roll a die to randomly select the first spell from the standard list, also give the five spells in order that follow it, then roll 1d20 twice to add or drop up to two spells. This gives 1st level M-Us a little bit of variation and increases the urge to adventure. ("Damn, I got Charm, but not Sleep? I better look for someone else's 1sr level spellbook!")

    2. I don't follow the 1d20 mechanic. How do you use the results of the 2 d20 rolls to add or drop spells?

      I am really leaning toward a "magic book" approach where all spell books are famous "published" tomes that also happen to contain the formulae for spells. I realize that this is a pretty big diversion from how people expect spells to work, so I haven't quite decided yet, but I really like the atmosphere of the eldritch tome copied down through the ages.

    3. I'll do a separate post on this, but the basics are: if the spell indicated by a d20 roll is one you already have, you drop it; if it's one you don't have, you add it; and if the result is higher than 8, no changes are made.