Turn Length

Using a Turn Length of 1 Minute (and Rounds of 10 Seconds); Advantages, and Agreement with the Original CHAINMAIL Rules

For quite some time, as you can see in the sidebar, I've interpreted the OD&D "round" as a short period of about 10 seconds in length (in accordance with pretty much anything developed after 1978).

But one thing I've had as a dilemma for quite some time is how to interpret the "turns" of OD&D, especially in regard to durations for spells and potions and the like (e.g., I left it undefined in the OED Book of Spells). I've gone back-and-forth in considering the AD&D-style 10-minute turn, or just saying a turn = round (10 seconds for me), etc. But what I've finally decided recently is to read occurrences of "turn" as 1 minute (for simplicity, say: 1 turn = 5 rounds). Truth is, it's even a throwback to the original game of Chainmail, for reasons which I'll outline below:

Advantages of the 1-minute turn:

(1) It's easy to interpret for players. When they look at the OD&D spell list and ask "what's a turn?" I can just say "1 minute" and no mental conversions are necessary.

(2) It matches what we might expect for the length of one scene. When I browse through the OD&D spell listings (usually 3, 6, or 12 turns duration) and think about the real-time length each spell "should" last, usually a few minutes (surely less than an hour) seems about right. God forbid I use the word "cinematic" here, but it is the case that an action beat in literature, television, movies, or music usually lasts on the order of a few minutes.

(3) It means we usually won't have to track spells in combat. Granted OD&D spells durations above (15, 30, or 60 rounds by the simple conversion), most of our combats will terminate before we reach these points. Admittedly there's a bit of a loss in not having the end-time of spells be a tactical consideration in combat, but it's definitely balanced by the ease of record-keeping.

(4) It's a return to the better-thought-out original rules in Chainmail. Recall that Chainmail starts its mass-combat rules with a "turn" of 1 minute (p. 8); and a smaller division of "rounds" for melee cycles (not well-defined, but you can see the distinction in the Fatigue rules, p. 11 -- thanks to UWSGuy for educating me on this). Interestingly, when Chainmail gets to the Man-to-Man rules, then it uniformly presents the action in terms of the "round" designator (see all of p. 25, etc.), even though later fantasy spells are in "turns" (p. 31-32). So this both makes sense as pacing and is compatible with what I'm doing here; "turns" of 1 minute, with man-to-man "rounds" of a smaller unit (like around 10 seconds, perhaps).

The fact that Gygax garbled the issue later when he got to OD&D Vol-3 by asserting that turns were 10 minutes, and rounds were 1 minute -- and then doubling down in defending the nonsense in the DMG -- shouldn't inhibit us from using an interpretation that is easy, sensible, and more true to the actual root of the game.


  1. First of all I would like to congratulate you on your blog and on your house rules for original D&D. Reading both has been an education for me.

    There is a thread on this issue at the OD&D Discussion boards which seems worth reading (http://odd74.proboards.com/index.cgi?board=adventures&action=display&thread=6497). A poster named Cooper points out that there is a distinction between melee turns and movement turns in the Greyhawk supplement (under the description of the Delayed Blast Fire Ball spell), even if this distinction is not generally clarified elsewhere in the rules.

    I just started an Original D&D campaign two nights ago, and I decided to interpret spell duration in terms of movement turns of 10 minutes in length. This resembles your solution in that it largely obviates the need for record keeping in a combat, assuming rounds which are 10 seconds in length (which I have done, following your lead). You make a good point that a dramatic unit is typically around a few minutes in length. However, presently I am swayed by considerations of utility vis a vis some of the spells. Take Light, for example. This has a duration of 6 turns plus one turn per level of the caster (Men & Magic, p. 23). If Light is to be useful in the exploration of the dungeon, these turns have to be interpreted as movement turns. A Light spell which is only 13 minutes in length would allow for little more than one turn of movement before being extinguished. Ditto for spells like Detect Invisible (Objects), described below on the same page; this is meant to aid in searching for invisible treasures and the like, presumably during movement turns. However, I wonder if some spells become overpowered if their duration is interpreted in movement turns instead of melee turns. Hold Person comes to mind.

  2. Sort of on-topic in re: the 1-minute round.

    In the past few years, I've interpreted the melee round as being an unspecified length of time, such that the actions of the combatants taken during the round could happen.

    After combat, I count up rounds as 1 minute apiece to account for after-battle resting, binding of wounds, cleaning of weapons, etc. So the one minute is sort of an abstraction.

    This interpretation gets problematic when looking too close and accounting for spell durations, etc.; I admittedly handwave that bit.

  3. It's certainly a problematic part of the rules, and the ambiguity (and contradictions) lets different people apply legitimate alternate interpretations. Personally I'm not fond of hand-waving it, because at some point it becomes a critical decision point for my players (do I fall this distance in one round, or can I cast a spell, etc.?)

    @ Jonathan: Nice link (recommend others check out the quotes there for more), and those are definitely key spells we both looked at for this concern. My take on light is that's what you can use to save your bacon if your lights go out in a given encounter (torch blown out as in DMG play example, doused in water, etc.)... but for long-term exploration, that's what continual light at 2nd level is for. I'm also okay with detect invisible being used in one location after some advance guesswork. Possibly the most troubling spell is actually water breathing (12 turns), which at least demands that the turns be longer than 10 seconds (at which point you could hold your breath approximately as long).

    And thanks for the kind words!

  4. As the original poster of the ODD74 thread, I couldn't agree more.

    Regardless of how one interprets the legth of a combat round, there is no doubt that "turns" in the spell descriptions are CHAINMAIL turns of 1 minute. The only change from that in OD&D occurs in Swords and Spells, where the turn length is increased to 2 minutes for no reason I know of.

  5. I have to say that I greatly prefer non-combat spells to last longer. Significantly longer. If a first level magic-user uses his only spell to cast Light, it should last more than a few minutes. I'd like to see it last all day.

  6. Light's definitely touchy... I might very well feel the same way if it wasn't for continual light just one step up. And I like having reasons to continue highlighting the fragile torch/lamp resources, etc.

    Anyway, at this point agreeing with DHBoggs here, good stuff.

  7. Speaking of the ODD74 thread, I am confused about one of Cooper's posts. He says that there can be up to 10 melee rounds in one combat turn. Does that mean that every combatant in the melee gets to make 10 melee attacks per combat turn? Or does it only mean that fighters and others with multiple attacks are said to fight for a number of melee rounds equal to their number of attacks per combat turn?

    Also, as Cooper points out in the original thread, Supplement I: Greyhawk lists the duration of the Fear spell as "6 turns (movement or melee as applicable)" (p. 23). This seems to provide a precedent for interpreting the duration of spells as either melee turns or movement turns, depending on context. Perhaps if a spell is cast during a combat, the duration is read as melee turns, and if the spell is cast during exploration, the duration is read as movement turns. That seems like a strange rule, but perhaps that's what Arneson and Gygax intended.

  8. I actually really liked the sound of that, throw spells, shoot arrows, then melee is joined, 10 combat rounds, or death or morale failure until the next combat turn and next spell.

  9. The fear thing seems like one-off glitch to me (temporary insanity). That's just the kind of scaling insensibility that I personally just cannot accept. (If it works for someone else, okay, of course.) I was also just reading Gygax in Dragon #15 where he vociferously argued against, and even apologized for that kind of thing -- "If one scale is
    tampered with, all of the others must be adjusted accordingly in order to retain a reasonable, balanced, and playable game" (and this article originated the shouty all-caps scaling adjustment on PHB p. 39).

    @ Jonathon: I think Cooper's trying to read Chainmail as strictly as possible. It wouldn't be related to number of attacks. The key is that in the Chainmail melee phase, you do hits and then consult a morale table (CM p. 15) that goes "0-19 difference -- melee continue; 20-39 difference -- back 1/2 move, good order; [and other retreating results up to 100+]". So as long as you keep hitting the 0-19 result, then you keep adjudicating more "rounds" of melee within the same "turn". Could be any number there, in theory; but probabilistically almost certain for it to be less than 10.

    Is that helpful (I hope)?

  10. I agree that it is a bad idea to have the same spell duration jump around from melee turns to movement turns depending on context. Perhaps that is how Gygax originally played, though, or perhaps fear is just a weird exception. Either way, I don't approve of it as a ruling, but it's at least of historical interest.

    The 1st edition AD&D PHB might help resolve the issue. As you know, Gygax changed a lot of the spell durations between OD&D and AD&D. However, the few spells I've checked seem to favor interpreting OD&D spell durations as melee turns rather than movement turns.

    Here are some of the 1st and 2nd level spells from Men & Magic which have a stated duration (with their AD&D counterparts listed in parentheses): Hold Portal, 2d6 turns (AD&D: 1 round/level); Protection from Evil: 6 turns (AD&D: 2 rounds/level); Light: 6 turns + 1 turn/level (AD&D: 1 turn/level); Detect Invisible: 6 turns (AD&D: 5 rounds/level); Levitate: 6 turns + 1 turn/level (AD&D: 1 turn/level).

    If OD&D spell durations were interpreted in terms of movement turns, then the duration of the spells would far outstrip their AD&D counterparts. Interpreted in melee turns, the OD&D spells are slightly shorter than their AD&D counterparts, though this is partly due to the fact that more AD&D spells have durations which vary based on caster level.

    Thanks for the clarification regarding Chainmail. I have read the rules, but I evidently completely misunderstood them, since I didn't realize that the "melee continues" result indicates that the melee continues in the same turn. Whoops.

  11. Agree with that observation -- I had a past post on just that (changes between editions highlight in yellow there). Most spells with durations in 1-minute "turns" in Chainmail converted to the same "turns" in OD&D (albeit defined as 10 minutes in Vol-3); then most of those same spells switched to the 1-minute "round" in AD&D.

    And I also never thought to interpret the Chainmail "melee continues" result as being in the same turn. It's totally not clear, and I naturally read it the same way you did. Then someone pointed out how much of the "turn/round" thing clarifies when you read it this way, and I have to agree. (And furthermore, there's the explicit example on p. 15-16 where units melee multiple times in a turn from continued charge movement: "... the two units will again melee that turn".)

  12. I'm preparing an OD&D campaign using your OED Player's Rules, and I'd like to ask for clarification on a few things.

    Let's say a character has a move rate of 12". Using the 1"=5ft scale, how much can they move in a turn (1 minute) or in a round (10 seconds)? Is it 120ft in both instances, since according to OD&D, a character make 2 moves / turn? Or 120ft in a turn (2 moves), but 60ft in a combat round (1 move)?

    1. Glad you asked: It's 12 x 5 ft = 60 feet in a round. In a turn of combat moves it would theoretically be 360 feet, but to date that's never come up. I just abandon the 10-minute exploring turn (and associated rules), and by default just gauge exploration in real-time. Check out the OED Judges Rules booklet and you'll see that under Dungeon Adventures: Movement (p. 5, with explanatory endnote). http://www.oedgames.com/

  13. I've been adopting 1 turn = 1 minute in my last few sessions since I've read this post. It really works great with most spells.

    I have to say that the more I play OD&D and try to "fix" the rules, the more it looks like something between your OED or BX.

    I'd like to point out though, that the GenCon (IX and X) tournment modules published by Judges Guild adopted the spell durations in 10 minute turns. Probably just following whats implied in the LBB.

    1. Thanks for saying that!

      Agreed, of course, that when the official rulebooks said 1 turn = 10 minutes, that certainly set a tradition. I do think Gygax was overly conservative about fixing basic unit mistakes like that (see the "Presumed Axiom" post, quoting Mentzer). If only he'd hewed to Warriors of Mars in the same year as OD&D where it's explicit that mas scale is 1 turn = 1 minute and man-to-man scale is 1 turn = 10 seconds.

  14. Question about your usage of 1" = 5' scale. Are you also incorporating the "indoor movement in feet, outdoor movement in yards" convention?

    1. Great question, it's a bit a gray area for me right now, honestly. Ideally I would *not* recognize that for simplicity.

      The problem for me (still being worked out) is that in the mass wargame, archery can certainly hit an army at a hundred yards away -- even though hitting a man at that range is effectively impossible. Granted that, there's an intuition that spells should be balanced to be able to strike from an equivalently long distance away.

      Say longbows fire 21" in the mass wargame. In an ideal world, I'd have no spell-extensions outdoors, and thus a fireball would only have 8" range. But I fear to many players are going to balk at that; arguing they should be a comparable 24", and that could be back-justified by the range extension. Somehow. Maybe either ballistic limitation or supernatural powers underground limiting the effect. Still thinking on that model...