Tuesday, March 29, 2011


THAC0 is an acronym for "to-hit armor class zero" in Advanced Dungeons & Dragons 2nd Edition, published in 1989. It represents the minimum target number needed by a combatant to hit or strike armour class (AC) zero on a d20 (i.e., on a 20-sided die). Against other armour classes, the target number is calculated by subtracting the opponent's AC from the combatant's THAC0. Thus, a combatant with THAC0 13 would need to roll 10+ to hit AC 3 (i.e., 13 − 3) and 18+ to hit AC −5 (i.e., 13 − [−5]).

THAC0 was a handy construct that replaced the combat matrices of the first edition game. In other words, instead of a table for each group of character classes showing the to-hit numbers by character level and AC, all THAC0 values were in a single table organized by character class group and character level. This reduced bookkeeping, for a player could simply record his character's THAC0 instead of writing out the to-hit number for each AC from 10 to −10. The DM no longer had to consult the to-hit tables, for a monster's THAC0 could be included in the stats provided by the scenario. It should be noted that THAC0 wouldn't quite work for first edition purists who used Gygax' "multiple 20" rule when the to-hit number was 20+.

Why mention THAC0 now, twenty-two years later? I invented it in 1983 (see page scans below), five years before TSR published it in FR6: Dreams of the Red Wizards, a first-edition product, and the earliest THAC0 mention of which I am aware. I called it T.H. ("to-hit"), but the concept is identical. If I believed in intellectual property, which contradicts actual (scarce) property rights, I might claim "ownership". As it is, I'm willing to settle for the honourary title of THAC0 Father—at the risk of annoying Mario Puzo's estate. On the other hand, perhaps it is inevitable that innovations which seem obvious in retrospect (retrobvious?), like THAC0, will be invented by somebody, making the idea of intellectual property ownership all the more dubious.

Above: Cover page of The Final Conflict, a typewritten adventure that uses the concept of THAC0, showing 1983 date.

Above: Page 17 of The Final Conflict, showing creature stats with T.H. (what TSR later called THAC0).

Next: "Playability vs. Realism".

Friday, March 25, 2011

Diary of a Madman

How do you learn how to play D&D the first time? Well, the best way was to sit down with somebody who already played D&D and sit in on it—because if you actually bought the thing from the word go and you weren't a gamer and you tried to learn how to play it, forrrget it [laughs]!

Caveat: this will probably only interest those who are curious about the autobiographical details of a 14-year old's introduction to Dungeons & Dragons, the mother and flagship of role-playing games (RPGs).

Nick P., a friend from that era, had received the D&D basic set (1981 Moldvay edition) for Christmas 1981. Nick had learned how to create characters, but neither of us, nor any of my close friends, knew how to play.

I kept a journal for grade nine English, my final year of junior high. My entry for Monday January 4, the first school day after the winter holidays, doesn't mention D&D; analysis of the rest of the journal reveals that I didn't have English class the next day (I had English on three days of the four day cycle), so my next opportunity to write about it was Wednesday the 6th.

On Monday the 4th or the next day I accompanied Nick to his parents' abode in Welsford Gardens, where he helped me roll up my first character, a thief named Vern; in my imaginative frenzy of anticipation, I over-equipped him. Vern was never played, as I recall.

As for the text itself, I have transcribed only the more noteworthy D&D-related entries. Errors and oddball formatting have been preserved. Subsequently-added details and comments are enclosed in brackets (aka "square brackets"). I attribute the poor writing quality to the coercive nature of the exercise; entries were rushed and sometimes padded with nonsense; hurrah, public education!

Scan of journal page

[Wed.] January 6, 82

Me, Nick [P.], Paul [R.], and Mark [P.] are going to have a game of Dungeons and Dragons with Paul Morris as the Dungeon-Master.

The basic game is to roll the dice to invent characters (Fighters, thieves, clerics, halflings, dwarves, elves, etc.) and to journey through dungeons, caves, etc. in search of treasure while fighting monsters along the way.

[My first D&D game wasn't played that day. Either our plans fell through or I bailed out. I instead purchased the rules at a local mall, as recounted in the next entry. Mark and Paul were schoolmates.]

[Thu.] Jan. 7, 1982

Last night I went to the Parkway Shopping mall and bought the Dungeons & Dragons basic rule book and Dragon dice. I think I'm missing the 10-sided dice [sic]. [sketch of dice] are what the dice look like.…

["Dragon dice"—at least I wasn't pretending to be cool.]

[Fri.] Jan. 8, 82

… I already know how to play Dungeons & Dragons basically.

[I learned the game by reading Moldvay's Basic edition rulebook. This was most likely on Wednesday evening (Jan. 6) after returning home from the mall with my purchase. It was probably on the same night or the next when I created my first dungeon, drawn on a half-sheet of paper; I used it to play my first game, as DM, with (if memory serves) the aforementioned Paul R., Nick P., and Mark P. as players. My next dungeon, which occupied an entire sheet of graph paper, was my oldest friend Steve H.'s introduction to the game. In only the first or second room, his party fled in terror at the approach of animated skeletons. As I recall, the skeletons made their presence known by slowly and stiffly rapping on a door, an idea inspired by John Carpenter's The Fog (1980), which we had both seen on the big screen. This episode illustrates the power of RPGs and is one of my fondest gaming memories.]

[Tue.] Jan. 12, 82

I know how to play Dungeons & Dragons completely and I am the Dungeon-Master (DM). It is the best game I've ever played in my entire 14-year life. In shop, I'm making a wooden box to hold my dragon dice.…

[There was no entry for Monday the 11th, as it fell on the only day in the 4-day school cycle in which I didn't have English class.]

[Thu.] Jan. 14, 82

Yesterday I was away 'cause my sister was sick and I had to take care of her while my mom was out. I also went to Don Mills and bought D&D module B1 "In Search of the Unknown". Its [sic] really amazing. On the way home the buses were very, very, very crowded—12 people to a 5x5 area approx.

[Tue.] Jan 19, 82

… On the weekend, I went to a store called "Good Stuff Games" or something like that in the Eaton's Centre to buy a new set of Dragon-Dice for D&D. They cost $1.00 each (I bought 6) and they are crystal plastic.…

[Prices are in Canadian funds. These dice, and 6 smoked dice purchased later, were literally stolen out of my hand as Steve and I were walking in our neighbourhood one evening. The thieves, who had been walking behind us, got away as I hesitated between pursuit and telling my friend what had happened. I spent the next hour or so patrolling the area, but was never able to identify the perpetrators.]

[Mon.] Jan. 25, 82

On the weekend I bought the D&D© Expert Rulebook.…

[Wed.] Feb. 3, 82

In shop I am putting the finishing touches on my CROSS-BOW which looks like [sketch].…

Dungeons & Dragons is still the thing I play whenever I get any free time.…

[Let this be a warning to you kids.]

[Thu.] Feb. 4, 82

… I designed a new dungeon, well I'm still designing it. First, the party comes upon a keep (castle), hoping to join. The castles [sic] garrison is about 30 strong. Soon the castle is under seige [sic], and the castellan (head of the castle) announces he will pay a 10,000 gp reward if they [the PCs] go through a trap door into a dungeon which leads to friendly men-at-arms that the castle desperately needs for defence. Unfortunately, the dungeon has a few lurking monsters and even if the party contacts the reinforcements there is a chance that the castle will fall anyway, ruining the reward.…

[The rest of the entry details the military forces involved. I don't think I ever ran this adventure.]

[Tue.] Feb 22, 82

In metal shop, Nick [P.] & I are making a two-handed sword. It will look like the picture on the back of this book.…

[I also made a battle axe and a short sword. The metal-shop teacher was reluctant to let us take them home.]

[Mon.] Mar. 1, 82

On Saturday I bought "The Advanced D&D Players Handbook" for $12.00 (no tax) and the AD&D Dungeons [sic] [Masters Guide] for (gulp) $17.00! Anyway, they are amazzzing!!! More details later.…

[These were purchased at the Battered Dwarf, a hobby store on Church St. in downtown Toronto. As Nick P. and I reached for the merchandise on the shelf, the shop clerk rather surlily informed us of the store's you-damage-it-you-buy-it policy; it seems his warning worked too well because the store would close the next year.]

Thursday, March the fourth 12:58:59 PM Nineteen eighty-two AD

Last night, I went to Don Mills Shoppin [sic] Centre with Steven [H.], Nick [P.], Mark [P.] & Roddy [F.] and I bought the AD&D Monster Manual for $13.98 (no tax).…

After school today, Paul Morris, Nick [P.], Mark [P.] and Roddy F. are going to play Roddy's module - B3 The Palace of the Silver Princess.…

[Roddy did DM this module for me and perhaps the others named, but I don't remember playing D&D with Paul Morris at any time before high school, which was the next year.]

Friday March the nineteenth 1:28, nineteen eighty-two A.D. James [M.] (not the actor) just blew a fart. WHEW! It carried across the whole room. [I apologize for forgetting to not transcribe that part.] So far, I have spent a lot of money on D&D:

BASIC RULEBOOK . . . . . . . . . . . . . . . . . . . . 7.95
DRAGON DICE . . . . . . . . . . . . . . . . . . . . . . . 2.50
CRYSTAL DRAGON DICE . . . . . . . . . . . . . . 6.00
EXPERT RULEBOOK . . . . . . . . . . . . . . . . . . 7.95
AD&D PLAYER'S HANDBOOK . . . . . . . . . 12.00
DM'S GUIDE . . . . . . . . . . . . . . . . . . . . . . . . 17.00
MONSTER MANUAL . . . . . . . . . . . . . . . . . 13.95
UNKNOWN MODULE . . . . . . . . . . . . . . . . . 6.95
CASTLE AMBER MODULE . . . . . . . . . . . . . 6.95
SECRET OF BONE HILL MODULE . . . . . . . 6.95
                    MODULE . . . . . . . . . . . . . . . . . . . 6.95
                                                                TOTAL $95.15

Last night (MARCH 30th) Roddy [F.], Steven [H.] and I played [Steven H.]'s AD&D module: TOMB OF HORRORS, levels 10-14. Boy, so far it is HARD.

[For the notoriously challenging S1: Tomb of Horrors, Roddy and I each played several high-level one-shot characters.]

Monday April the nineteenth
1:26 AM one thousand, nine
hundred and eighty-two AD

… I have finished my Dungeon A2 "Shrine of Terror" with 30 pages of description, 2 pages of maps (6), 7 pages of visual aids. It is my best dungeon ever. You start out at the very top of a pyramid, enter & descend in levels until you get to the sixth level (the dungeon) fighting monsters [and] a few mummies until you get to "Ankhamun's Tomb" where Ankhamun (a super mummy) will fight to the death.

[Obviously influenced by S1: Tomb of Horrors.]

Next: "THAC©".

Thursday, March 24, 2011

Evolution of an RPGer


As a lad I was a self-taught casual wargamer. Like many boys, my oldest friend Steve H. and I had cheapo plastic GIs; but an increasing interest in the Second World War around the age of ten led to my acquisition of historically-accurate HO-scale plastic soldiers (mostly Airfix) and ordnance. I knew of H.G. Wells' Little Wars but never saw a copy and didn't learn the details. With Roddy F., a friend I made at age 12, I conducted an alternate-reality simulation of the war, complete with plans, reports, and maps as though we were personally directing the Wehrmacht. Battle outcomes were the culmination of hits and misses based on eyeball estimations; it did not occur to us to quantify data or to use dice or other randomizers. Casualties were pro-rated according to the ratio of toy soldiers and equipment fighting in a representative battle at the tactical level to the forces that were participating at the strategic level. We lost interest during the German invasion of the British Isles (invasion areas were Cork, Inverness, and Plymouth). At around the same time, my grandfather (one of the youngest RAF pilots of the Second World War) gave me the 1977 edition of Avalon Hill's venerable D-Day wargame, which used a hexagonal gridmap, dice, and combat tables.

Years earlier, Steve H. and I made up a kind of paper wargame. We drew floorplans of castles and garrisoned them with symbols representing crossbowmen and other defenders. We then added attacking troops and played out a siege by redrawing forces in their new positions after each combat exchange. Ranged attacks were resolved by "skating" a pencil tip along the desired trajectory by means of an index finger precariously placed on the pencil's other end. Even if we had thought of applying dice and mathematics, Dungeons & Dragons had already beaten us to the market.

Dungeons & Dragons

My first real exposure to Dungeons & Dragons was in 1979 or '80. A Toronto hotel was hosting some kind of expo for smart, creative kids, and I was offered the chance to attend by my avant-garde grade 7 teacher. I was accompanied by Arthur D., a friend and classmate with whom I had made a stop-motion Super 8 animated short depicting a space battle. In one small room or partitioned area of the hotel convention area, a group of older teenaged boys were gathered around a table covered with graph paper, books, and dice. I was vaguely aware that Dungeons & Dragons, which was only about five or six years old at the time, involved bearded gnomes, caverns, and treasure chests. The game seemed whimsical at a time when I was more interested in warfare and the horror genre, so I made no attempt to learn how it was played.

In 1981, Nick P., another friend and classmate, received the Tom Moldvay version of the Dungeons & Dragons Basic Set for Christmas. We didn't know how to play, so I spent an hour or so excitedly poring over the rulebook. It was a revelation and the beginning of a decades-long obsession with role-playing games. Soon I had recruited my friends Steve and Roddy, and the three of us would play Advanced D&D regularly on weekends for the five years that remained before adulthood started interfering. We took turns DMing each other in four-session rotations, using and abusing Tolkien's Third-Age Middle Earth as a common setting until we each created our own worlds. Other friends gravitated towards our "Sunday Group". A few of us played other games on occasion, such as Call of Cthulhu, Top Secret, Car Wars, and Paranoia. Around 1988-89, Ed Greenwood himself DM'd some friends and me in his intricate Forgotten Realms campaign setting, which we played on Saturday mornings in the undercroft of Brookbanks Public Library in Toronto, where he worked.

Cells & Serpents

We had our own house rules, of course (nobody played straight AD&D, Gary Gygax included), but my dissatisfaction with certain D&D game mechanics led me to design my own game. I created Cells & Serpents around 1988. Taking a cue from pre-d20 Chaosium, the base mechanic was a d100 roll, from which I created a unique combat system with elements borrowed from GURPS, Top Secret/SI, and good old D&D. The Rolemaster Character Law skill system was grafted on, and the magic system was based on Rolemaster's Spell Law. This worked well for the time I used it, probably until around 1997. By this time we were playing only sporadically. Roddy had moved away, Steve was spending more time playing with another group, and much of my free time was soon to be devoted to my new purchase, a 1998 Chevrolet Camaro SS. I went on de facto hiatus as DM, but continued as a player while other friends stepped behind the DM screen.
1998 Chevrolet Camaro SS

Mailed Fist

The excellent Ars Magica game, which I read around 1994, inspired me to rethink Cells & Serpents. My system contained D&D remnants that compromised playability, such as numerical scores for abilities like strength and dexterity that were meaningless in themselves but which had to be translated into the numbers that were actually used in the game; Ars Magica avoided this middleman and expressed ability scores as direct values. Both Ars Magica and Dungeons & Dragons 3rd edition (and later) employed an elegant base mechanic: for an action to succeed, a die roll + any relevant modifiers must match or exceed a target number that represents the action's difficulty.

I dropped the name Cells & Serpents when an Internet search revealed that it already belonged to a computer game. The new game was dubbed Mailed Fist. As of this writing, most of the heavy design work is complete.

Next: "Diary of a Madman."

Tuesday, March 22, 2011

How to Teach Role-playing Games by Stealth

Bob: Nice apartment, Alice. Very secure, too.
Alice: Plus, I have a stun gun. No worries.
Bob: Note to self.…
Alice: Pardon?
Bob: Huh?
Alice: Nə—
Bob: Let me ask you something—just for the fun of it. What would you do if, while home alone one night, you heard a sound at your front door? A muffled thump.
Alice: I'd hit the mute and listen. Why?
Bob: Think of it as a type of thought experiment.
Alice: Cogito ergo ludicrum: I think, therefore I’m game.
Bob: I might have to steal that line. Okay, back to the scenario. Your hypothetical self suddenly remembers hearing a sharp click a few minutes earlier. It came from the front door, but you dismissed it as unimportant.
Bob: Let's say you hear it again. A single thump on the door, like the soft rap of a hand.
Alice: Is this your modest way of relating an anecdote, Bob?
Bob: Not really, but I know you like mystery stories.
Alice: True, dat. Well, I surmise that someone would have to be out there.
Bob: Or something. (Sorry.)
Alice: Nah. I'd probably think it was a kid playing a prank.
Bob: After midnight?
Alice: That is late, but you know kids these days. I think I'd note the time, in case I'm ever needed as a witness. Such are the benefits of reading crime fiction.
Bob: Okay, but then what?
Alice: Just to be sure, I'd take a pencil and a scrap of paper from the coffee table and write down the date, time, and heard thump on door—it could become my alter ego’s epitaph. I'd slide the note under my Leonard Malton’s Movie Guide—also on the coffee table. Then I’d stand up and tip-toe to the door.
Bob: It'd be absolutely quiet, so every little noise you make would seem loud. You wouldn't be sure nothing heard you.
Alice: You're starting to scare me, Bob. But as you know, I do enjoy a good chilling of the spine now and then.
Bob: Let's say you reach the door. What now?
Alice: Look through the peephole. What's there?
Bob: At first you think it’s a person. At eye level a few feet in front of you is a bowler-style hat. It appears to be perched atop an upright broom handle or maybe a cane.
Alice: Freaky. Have you read "Thurnley Abbey"? Never mind. Wouldn't I see or hear the perpetrators?
Bob: The peephole gives you a wide-angled view down the passage leading from your apartment door. No one's there and it's deathly still. Until the weird scarecrow thing suddenly jerks towards you! As you jump back, there's another muffled thump on the door.
Alice: Run away! No—wait. Wouldn't Occam's Razor say that the broomstick simply fell over? Talking shaving paraphernalia have yet to let me down.
Bob: As you're mulling this over, irked that your wit may forever lack an audience, you notice that the front door is being pushed open from the other side.
Alice: Ah! What to do? My stun gun's in the bedroom. The bathroom door is lockable but flimsy. My phone is in the living room. Is there time to leap forward and slam and deadbolt the door?
Bob: Well, coming through the gap of the partially-opened door is the end of a thin stick a-tapping. Oh, and speaking of time, I must be on my way. It's late and I have a blog post to write.
Alice: But what was that about? What was at the door? What happens to the other me?
Bob: Important questions all, but the answers will have to wait.
Alice: Call me.

Next: "Evolution of an RPGer".

Saturday, March 19, 2011

What is a Role-playing Game?

This blog is about tabletop role-playing games (RPGs). Non-tabletop forms include live action role playing (LARP) and electronic gaming.

Tabletop role-playing games can be mysterious to those who have not tried them. Their immense variability (genres, characters, scenarios, settings, etc.) can make examples misleading, masking the underlying concepts.

A functional/procedural description:
  1. The gamemaster describes your character's perception of the present situation.
  2. You tell the gamemaster what, if anything, your character does or tries to do.
  3. The gamemaster determines the results of your character's efforts.
In step 1, the gamemaster also divulges any relevant information that the player lacks but which his character is presumed to know or believe as a result of his background and experiences, which are assumed to be as rich and detailed as a real person's. In addition, players are entitled to ask the gamemaster for elaboration based on what the character is able to observe; for example, if the gamemaster mentions a horse that your character sees, you can ask for its colour, size, etc.

For the purposes of step 2, not doing anything (e.g., standing still) is considered an action. Furthermore, what counts as an action varies with the current time-scale. During combat, for instance, where the time scale is typically moment-by-moment, actions—such as striking a blow, drawing a weapon, or moving to another location—are correspondingly brief and immediate. On the other hand, the time scale for cross-country travel might be hourly, daily, or longer, depending on the distance to be covered and the level of detail the gamemaster wants to bring into play; an uneventful, routine journey can be narrated in a few words.

In step 3, the gamemaster determines whether your character's action succeeds. Dice (or other randomizers) are used to resolve uncertainty, such as whether an arrow finds its target. Routine endeavours are typically assumed to succeed. Nevertheless, all player-character (PC) actions, no matter how trivial-seeming, are subject to gamemaster approval. The gamemaster then incorporates the results of your character's action into the new status quo, which is then described in step 1 as the cycle is repeated, ad infinitum.

A role-playing game, then, is an endlessly iterative process. Characters are immersed in and interact with an imaginary world, constantly bringing about a new state of affairs. (Fans of German philosophy might recognize a pattern of thesis-antithesis-synthesis.)

The gamemaster, who alone decides and fully knows what is true inside the game universe, represents himself to the players as their characters' senses and sometimes their memories. In this role, he is supreme master of the in-game (fictional) reality. To the players he is like Plato's cave master, Descartes' evil daemon, or the simulated reality in The Matrix.

A crucial distinction between role-playing games and conventional storytelling is that the gamemaster does not control the protagonists; the players do. While the player controls only the will of his character (virtually everything else is managed by the gamemaster), his role is anything but insignificant, for the game is always centred on player-directed character exploits.

Yet a player never has total freedom of action. For instance, his character must contend with obstacles and barriers within the game world, such as antagonists, monsters, or difficult terrain. In addition, the gamemaster can try weaving plotlines into the characters' lives, but players seldom do what is expected, tempting the gamemaster to introduce a deus ex machina. Not surprisingly, the excessive manipulation of events by the gamemaster is frowned upon. Termed railroading, it transforms players into mere spectators, undermining the essence of the game.

Nonetheless, the gamemaster will sometimes override a player's control of his character—either to simulate the loss of free will, such as when succumbing to a Siren's song; to prevent a player character from acting on knowledge that he doesn't have (meta-gaming); to compel behaviour to which the player had already committed himself; or to retire a character from active play, effectively converting his status to that of non-player character (i.e., a character under gamemaster direction).

Being a game, it is natural to wonder how one wins. But role-playing games aren't about winning; their open-ended structure precludes ultimate victory conditions. The goal of role-playing games is for players to have fun, to experience the thrills of danger that are as real as imagination permits. Gamemasters try to make the fictional environment compelling and engaging. Character motivations, on the other hand, are for the player to choose. Whether he succeeds or fails, the character's life—and the game—goes on.

Players don't lose even if their characters die; in adventure games, the threat of death must be credible to maintain excitement. Thus, characters are occasionally lost, often heroically or tragically. But unlike in real life (as of this writing), the player simply creates another character and rejoins the game. And, until real life catches up, let the game continue!

Next: "How to Teach Role-playing Games by Stealth".