The Lost Caverns of Tsojconth (December, 1976) by Gary Gygax.
Additional credit for the WinterCon V version goes to Will Niebling, Scharlotte Niebling, Bob Karalunas, Howard Dawson, Joe Tomassi, Paul Wood, Kathy Wood, Laurie Van De Graaf, John Van De Graaf, and Mike Bartnikowski.
On the front page of the AD&D module, Gygax states:
The Lost Caverns of Tsojcanth was originally designed for the official "Advanced Dungeons & Dragons" Game Tournament at WinterCon V and contains the original tournament characters.*
*some details for the pregens were tweaked for the AD&D version
The inspiration for the Greater Caverns was derived from the map for Rob Kuntz's El Raja Key level 10, which had been repurposed for the Expanded Version of Greyhawk Castle core level 7.
Maps for ERK level 10/GC core level 7 (left), the Greater Caverns of the Lost Caverns of Tsojconth/WinterCon V (center), and the Greater Caverns of the Lost Caverns of Tsojcanth/module S4 (right).
Copies of "The Lost Caverns of Tsojconth" from WinterCon V can be pricey to obtain. There's a copy presently for sale at Noble Knight Games for $7995.
For an in-depth comparison of the WinterCon V tournament dungeon to module S4, including publication history and reviews, check out grodog's S4: The Lost Caverns of Tsojcanth page.
I had a great time participating in a session of "The Lost Caverns of Tsojcanth" at Gary Con X in 2018, and even played Flemin, who I run as an NPC in my home campaign.
The Lost Caverns of Tsojconth:
The tournament background is printed on the front cover:
Several decades ago when the Archmage Iggwilv brought the Marches of Perrunland under his domination, considerable store of treasure was taken from that place and sequestered by him somewhere in the no man's-land between the Duchy of Geoff and the forsaken Sea of Dust. Among his loot were several rare and prized tomes and the fabled lamp known as Daoud's Wonderous Lanthorn.When Iggwilv was slain by the Demon Graz'zt, and his minions scattered by an uprising of oppressed subjects, rumors began to spread regarding where the Archmage's treasure trove was located. Considering the cartloads of precious metals and gems taken away during the overthrow, it is not surprising that most of these whispered suggestions were ignored as spurious. However, the books and Lanthorn were never found, and the rumors did reach some interested parties, for several expeditions have sought to locate these items, but the parties were either unsuccessful in their attempts to find the location of the Caverns of Tsojconth (where the most reliable rumors claim the treasure rests) or else failed to return.
The possible location of the Lost Caverns "somewhere in the no man's-land between the Duchy of Geoff and the forsaken Sea of Dust" is similar to "the Barrier Peaks which separates the Duchy from the Sea of Dust" in the background for "Expedition to the Barrier Peaks"
Map of the Great Kingdom from Domesday Book #9 (1971) indicating "the no man's-land between the Duchy of Geoff and the forsaken Sea of Dust."
Gygax explained who Tsojcanth* was, in this interview:
I imagined him as one of the exceptionally potent magic-wielders who arise amongst humans every so often. I considered him the channel used by the Good deities for the further abridgement of the actual Tharizdun, as it were. Tsojcanth and a circle of other mages of good alignment, and certainly others of like persuasion and other capacities, assailed and defeated the followers of the avatar Tharizdun, and then by sympathetic means, and empowered by deital power, Tsojcanth (and his associated mages lending their power to him so as he could survive channeling of deital energies) forced the avatar Tharizdun to rejoin its parent entity.I did not identify Tsojcanth as to race, but I think he was more likely Flan or Oeridian than a Suloise. He was certainly human and of Good alignment.
*the original spelling of "Tsojconth" was apparently a typo, and "Tsojcanth" was invented merely "to sound exotic".
The set up for the tournament is clever:
You are a member of a group of six adventurers, met by chance some weeks past. Each was seeking the Caverns, each possessed a fragment of information regarding them. Together you have compiled what seems an accurate set of directions to the entrance of these caverns, and you are certain that the Archmage has filled them with fierce creatures to prevent trespassers from gaining their goal. A fragment of parchment you have states: "The right way is narrow...(words obliterated)...eam lies the straight pas...(more smudged writing)...pe the span swiftly of plunge to doom where the wat..."
and, here's the twist:
The Caverns of Tsojconth are a nexus in probability, where several alternate worlds touch. Each of you is aware that numerous parties such as yours, each containing six alternate persons like each of you, will be entering that part of the Caverns which manifests itself in their respective worlds. As each group adventures through the upper caverns one of their number will gain a certain aura, and he or she alone will be able to enter the lower level, while the rest will have to turn back. The chosen from each party will meet - possibly with one or more of their alter egos - when the descent to the lower caverns is made.
This feature of the Caverns can be used to facilitate travel between alternate game worlds, such as the World of Greyhawk, the Forgotten Realms, or even Mystara.
The six tournament characters possess levels ranging from 6-10 (accounting for multiclassed characters), with an average level of 7.8, including a half-elven fighter/magic-user/thief (as per the Greyhawk supplement). These make for great NPCs in your own campaign:
Cathartic (human), 7th level cleric, "worships St. Cuthbert of the Cudgel"Ethelrede (human), 8th level fighterFlemin (dwarf), 6th level fighterDunil (hobbit), 9th level thiefWeslocke (elf), 4th level fighter/9th level magic-userHockerbrecht (half-elf) 4th level fighter/4th level magic-user/5th level thief
Names were contributed by Howard Dawson, according to Paul Stormberg, in this thread. Equipment is listed with location-based encumbrance, as discussed in a recent post over at Zenopus Archives.
The AD&D version is billed as "An adventure for character levels 6-10" and contains AD&D versions of the six original pregens, plus two more (Arocken, a 6th level ranger, and Benedict, a 6th level cleric), with an average level of 7.4
The neo-otyugh (left) and troglodytes (right), two new monsters from "The Lost Caverns of Tsojconth". Illustrations were likely by David Sutherland, although erroneously attributed to Gygax in this disapproving review by Ken St Andre in Supernova #28 (July, 1977).
"The Lost Caverns of Tsojcanth" introduced several new monsters, including the giant snapping turtle, neo-otyugh, troglodytes (which made it into Holmes), and the water weird (attributed to Ernie Gygax, in the preface to the 1e Monster Manual).
There's also a reference to "Chinese" hill giants. Given the properties of the nexus (which might account for the presence of so many creatures), these might have originated from the Chinese region of the OD&D Game World, and speak a Chinese language.
Module S4 continued in the same tradition, introducing several previously unknown creatures, which were later included in the AD&D 1e Monster Manual II.
Using "The Lost Caverns of Tsojconth" in your OD&D campaign:
The Lesser Caverns represent a straight-up, classic dungeon crawl, although access to the core of the nexus in the Greater Caverns provides a unique and rewarding challenge.
Motivation for the PCs could include exploration or utilization of the magical properties of the nexus, possibly as a means of entering an alternate world.
I enjoyed running the original version of "The Lost Caverns of Tsojconth" for my group - you can read about our experience, complete with tactical illustrations, in our campaign journal.
A few years ago, I mocked up a version of "The Lost Caverns of Tsojconth" in the style of B1, borrowing flavor text from the later version. You can download it, here.