Thursday, April 20, 2017

Marked 20-sided Die

TSR's original dice set was included in Holmes Basic, Gamma World and sold separately

In the 1970s, rolling 1-20 wasn't as straightforward as today. The original dice set available from TSR included a white 20-sided dice, but it was numbered (and pre-inked) with 0-9 twice rather than 1-20. So these dice were actually d10s, and were most easily used to generate percentiles by rolling the same die twice in row or by rolling two different colored dice together. TSR even sold a separate white and pink set of Percentile Generators.

But since the beginning D&D has always needed d20s, for attacks and saving throws. The earliest D&D rulebooks don't explain how to use the 10-sided die to generate 1-20, but by the time of Holmes Basic, there was a recognized need to explain this, as the rulebook teaches two different ways to roll 1-20 with these dice. One is near the end of the book in the section "Using the Dice", which isn't in the Holmes manuscript, and so was added by TSR. This method uses a secondary "control" die to determine if the number is 1-10 or 11-20:

"For example: to generate 1-20, roll the 20-sided die and 6-sided die, and if the 6-sided die comes up 1-3 , the number shown on the 20-sider is 1-10 (1-0), and if the 6-sider comes up 4-6, add 10 to the 20-sided die and its numbers become 11-20 (1-0)".

The other method is described in the main part of the text in the section on Saving Throws (page 14). This was written by Holmes as it is found word-for-word in the manuscript:

"Numbers can be generated as follows: Mark one set of faces on a 20-sided die by coloring with a red permanent marker on one of each faces — 0, 1, 2, 3, etc. The marked faces will be considered to have a ten added to them — 1 = 11, 2 = 12, 3 = 13, etc. Unmarked
0 = 10, marked 0 = 20. This die will also be used to determine the results of combat from the combat table."

The picture at the top of this post (from an Ebay auction that indicated the dice were from a Basic set) shows an example of this: the owner has colored half of the faces of the 20-sider in a red color. The white faces represent 1-10, and the red faces represent 11-20. As I mentioned above these dice were pre-inked, so one couldn't just color the two sets of 0-9 with different colored crayons, the faces had to be marked to differentiate them.

This method is referenced again in the section "Combat Melee":

"The probability of a hit is converted into a random number of 1 to 20 (the specially marked die is recommended)" (page 18) and "A 20-sided die must be marked or colored so that
one set of sides 0-9 is different from the other set. Count 0 as a 10. The marked set is then read as if 10 had been added to the roll (11-20), treating 0 as 10 or 20. This die is used for all combat resolution" (page 19)

Holmes probably learned this marked die method from other gamers, as there are earlier examples of it. For example, below is an auction photo from last year, for an auction you may have heard about, an original woodgrain D&D set that sold for over $20,000. Included with the set in the auction was a 20-sided die and a note (with the date of ~1974 given by the auctioneer). In the note we see similar instructions, with the white half of the die being 1-10 and the orange half being 11-20.

In 1979, the 1st edition DMG still assumes use of these 20-sided d10s in the section "Dice", on page 10:

"If a d20 is used either 1-20 (assuming the use of a standard d20 which is numbered 0-9 twice without coloring one set of faces to indicate that those faces have 10 added to the number appearing) or 1-40 (assuming that one set of faces is colored) can be gotten by adding 0 if 1 or 2 is rolled on the d4 and 10 or 20 (depending on the die type) if a 3 or 4 is rolled"

The structure of this sentence is complicated, but Gygax is saying to use d4 control dice to turn 1-10 into 1-20 (for an unmarked die) or 1-20 into 1-40 (for a marked die).

This was a short-lived era as other manufacturers began cranking out dice. 

At some point (I don't have a date but will update this post if I find it), 20-sided dice that were not pre-inked appeared, which allowed for coloring the two sets of numbers with different colored crayons. You still had to remember which color was low (1-10) and which was high (11-20). I have a dice like this that I received in an auction a while back (I can't even remember what it came with):

I also don't know when the first 20-sided dice that was numbered 1-20 first appeared, but the standard d10 appeared around 1980, possibly debuting at Gen Con that year

In the last printing of the Holmes Basic rulebook, dated Dec 1979 but certainly from 1980 as it is the third version with that date, the section on "Using the Dice" was revised to refer to "the assortment of 4-, 6-, 8-, 10-, 12- and 20-sided dice" (page 46), and the portion about the control die no longer refers to 1-20. Holmes' instructions for making a marked d20 is still found in the section on Saving Throws, however.

The Acaeum reports that some sets of Holmes Basic include a set of six dice. I've never actually seen one of these sets. It does seem strange TSR would revise the rulebook to refer to the 10-sided die without actually including it. But I'd like to see it confirmed that a set shipped this way versus having dice added later. A complicating factor is that Holmes Basic set was sold up until at least 1986 (I have a catalog from then listing it), so some may have had 6-dice sets added to them at later date.

Certainly by the time of the Moldvay Basic set and Dragon Dice, both from 1981, we have the standard 1980s set of six dice, including both the 10-sided die and the 20-sided die numbered 1-20.

See also:
Veteran of the Dice Wars
TSR Ads in Boys Life 1977-1982

And Jon Peterson's articles on the history of dice in D&D: 
How Gaming Got Its Dice
The Origins of Dice Notation


  1. there is also a comment in the DMG mentioning colored die faces in the gambling section, page 215:

    In Between: Roll 3d20 — 2 white and 1 of a different color. The player must roll in between the 2 white dice with the colored die. Equaling a number is a loss. If the 2 white dice equal each other, the loss is automatic. Odds are always 5:2 before dice are cast. Note: A crooked house might paint 11 sides of
    a die black and only 9 red.

  2. That's great! I wonder if Gygax had a player try to pull that on him? : )

  3. Zack, could you please shed some light on the cardboard chits I received with my Holmes Basic? They were untouched and still in sheets.

    1. My original set when I was a kid had the chits and boy was I confused about how to use them. The conventional wisdom is that they temporarily replaced the dice in Holmes Basic when there was a dice shortage. I'll have to do some research and write a post about them - hard to believe I haven't already since they are so infamous.

    2. They worked fine, though passing around the dixie cup marked "20" slowed down my first game or two!

  4. I remember playing convention games in the early 1980s where DMs didn't trust players using the "new" d20s numbered 1-20: they wanted a control die rolled as well. I always found this interesting, since I assumed there were probably many more d6s out there that were weighted/cheater dice, but I think it was to prevent a player from inking more than 10 of the numbers to add 10 to the base number rolled.


  5. When I played with EGG in 1988 he was still using one of these dice - a white d20 with one set of faces marked in gray. He claimed he'd been using that die to kill PCs since 1972 :)

    1. Now that's an Artifact!

      I searched his Q&As, and by Jan 2004 Gygax had lost this die:
      As it happens I have quite a number of the old low-impact
      dice around here somewhere. The points on the d4 were very
      sharp but wore down quickly. Rob had a d20 that would stand
      on a worn point about one roll in 50 ;)

      Somewhere I lost my d20 with half the faces colored gray. It
      was my "killer die" that rolled an inordinate number of 20s,
      and the players really hated it ;)


      Source: Gary Gygax Q&A on EnWorld, Part V

    2. Here's another reference to this die - in response to you later in the same EnWorld thread:
      "It was either my gray or red "killer die," undoubtedly. It has since sent a large number of adventurers to their doom when rolled on behalf of my OD&D game "Old Guard Kobolds." The ninth party of six or more 2nd level characters fell to them at JanCon last month."

      Source: EnWorld Q&A

    3. One more, from March 2003. This explains that he'd lost the grey one, but still had the red one:
      "Those low-impact d20s did get pretty round in short order--well short order in terms of gaming time. Rob Kuntz had one that would stand on a point now and again. I still have a couple that I use when playing OD&D as the DM. One with gray faces on 10 sides is a "killer" die that comes up on those faces a lot--the 11-20 range, of course! Can't find it now, but it's likely in a box of old dice somewhere in the basement here. I have a second one with red faces that's as good for the monsters' rills, of course"

      Source: EnWorld Q&A

  6. Those original dice, man o man, would the edges round over in a hurry. They were from China, or Taiwan? I recall Gygax mentioning that TSR first got them through an educational supply company out west. Then directly from China/Taiwan.

    There was an intermediate step between dice numbered 0-9 x2 and dice numbered 1-20. It involved using a plus sign next to one set of the 0-9 markings. These dice, and the 0-9 x2 variety, are still available via direct order from GameScience-- the web site is easily found (not sure how you feel about such links in your comment section). We would require the die roller to call out 'dark high' or 'light high' to indicate which set of 0-9 represented 11-20. The default was the dark colored numbers were the 11-20 range if the roller didn't state which he wanted.

    1. the new +20s from GS are crap. The opaques have convex faces which cause the dice to roll around a lot more than the vintage dice, and oftentimes come to a spinning stop, while the translucents often have an awkward bit of flashing from where they were removed from the sprue, which needs to be clipped and filed down. None of my 80s era 1-20, +20, or 0-9x2 GS dice ever had these problems.

  7. One of my 20something players received a 1st edition DMG (revised cover) and a set of late 70's dice, including the "+1 to 0" d20. I explained to him that in the old days, the first d20's didn't have room for the 2nd digit, but apparently a "+" symbol fit just fine, and if you rolled a +1 through +0, you added ten to the # to get #'s 1-20. ;)

  8. I never saw anyone clor the whole face of the die back in the old days, we always incked with a different color or crayon. Coloring the whole face would have actually been easier to read.

    1. Use the wrong marker or crayon and watch those dice with whole colored faces stick to the table on hot, sticky summer days. :D
      (Before we had central air, of course...)

  9. Oh, cool. I still have the d4 from that set but the rest have been lost under furniture or to pilfering cats over the decades.