Greyhawk Castle Source Reference

How do we know what Greyhawk Castle looked like, and how it played?

Note: References of the form #123 refer to the posts in the ENWorld Q&A, entry 6 in below list.

1. OD&D The Underworld and Wilderness Adventures booklet, 1974. The Original D&D rules contain dungeon design guidance, spells, monsters, random encounter tables and guidelines for placing monsters and treasure which reflect the density and nature of monsters per level. It includes a sample map with traps and tricks as well as a list of mapping confusion tricks, all of which likely derive from Greyhawk Castle. 
2. Gygax Q&A, dated 15th September, 2005, in response to a question from user Clangador, part of [6]
3. HOW TO SET UP YOUR DUNGEONS & DRAGONS CAMPAIGN, Europa 6-8, p. 18ff, 1975. This is one of the most information dense pieces from the multiple ones Gary published in fanzines, with insight how the campaign grew as well as how the dungeon looked like.
4. Expedition into the Black Reservoir. El Conquistador Magazine, 1975
5. The Magicians Ring, Wargamer’s Digest – Volume 2, Number 8, June 1975
6. ENWorld Q&A Forum with Gary Gygax
   
7. Castle Zagyg, CZ2: The Upper Works, Troll Lord Games, 2008, Foreword and commentary
8. Hints for D&D Judges, Dragon 2, 1976
   
9. A photograph of Gary that shows his original level 1 map with key
   
10. A photograph of Gary with the level 3 map
11. Dragonsfoot Q&A Forum with Gary Gygax
12. Deogolf's Play Reports of Abridged Castle Home Campaign, 2004-2005.  Gary asked them to stop disclosing more detail after the April 7th post.
1. Castle Zagyg/Greyhawk intro post by Deogolf
2. Castle Zagyg/Greyhawk session Feb. 3rd, 2005 part 2 Post by Deogolf
3. Castle Zagyg/Greyhawk Campaign February 10, 2005 Post by Deogolf
4. Castle Zagyg/Greyhawk session Feb. 17, 2005 Post by Deogolf
5. Castle Greyhawk Session Feb. 24th, 2005 Post by Deogolf
6. Castle Greyhawk/Zagig session March 24th, 2005 Post by Deogolf    
7. Castle Greyhawk/Zagyg Mar. 31st, 2005 Post by Deogolf
8. Castle Greyhawk/Zagyg April 7th, 2005 session Part I Post by Deogolf
9. Castle Greyhawk/Zagyg April 7th, 2005 session Part II Post by Deogolf
13. EN World Game Play Report, 2007
14. WinterDark Con Play Report, 2008
15. Founding Greyhawk, Dragon Magazine Annual 2, p. 96-99, 1997 
16. Up On a Soapbox series, Dragon Magazine 287-320, by Gary Gygax and Rob Kuntz, 2001-2004
17. Gary Gygyax Forum post on Pied Piper Forum, Feb 16, 2004, part of [38] 
18. Hall of Many Panes level, that is intended to be a throw-back to old-school dungeon exploration, although this likely has no direct relationship with the maps or encounters in the castle
19. "If You Are Wondering What Dungeons & Dragons Is All About...", play reports for a hand-out called used to introduce players to D&D at GenCon VIII 1975 or Origins II 1976 that was played at GaryCon 2014. It featured the same map, but clearly different monster keys. There also is a transcript of some of the text document from an auction on the odd74 boards.
20. March 1975: Supplement 1 - Greyhawk includes updated random encounter tables, additional spells, monsters and magic items, and an expanded list of tricks and traps that all likely came directly from the campaign. This was based both on Greyhawk Castle, and on Gary's play in Rob's campaign, and covered material not included in the release of OD&D in early 1974 to late 1974. So these expanded lists likely reflect already the Expanded Castle. [15]
21. November 1976: Dungeon Geomorphs Basic Dungeon are relevant for expected dungeon layout and design -- they show lots of labyrinthine corridors and thin walls. On the subject of his use of empty rooms and map layouts, see also Deltas On Empty Rooms. 
22. December 1976: Lost Caverns of Tsojconth (MDG publishing) - note how the monster encounter key matches that from level 1 of Greyhawk Castle in style to see its closeness to CG. Tomb of Horrors and Expedition to the Barrier Peaks were written before Lost Tsojconth – they were used as adventures at earlier conventions.
23. April & May 1977: Dungeon Geomorphs Caves and Caverns & Lower Dungeons, reflecting the known lower levels that consisted of caves and caverns.
24. 1978: B1 In Search of the Unknown is included here even if it is not from Gary as it seeks to mimic the design guidance with typical tropes (factions, wind blowing out torches, magical pools, labyrinth of 10x10 rooms and doors, teleporters to confuse, population of kobolds, goblins and orcs, giant rats, paper thin walls, diagonals, magic mouths, secret and one-way doors, pit traps. It does however have very few empty rooms. 
25. 1979: AD&D DMG while written a good time after the original campaign, it was written by Gary alone and draws on his experience as a GM. 
26. 1979: B2 Keep on the borderlands written by Gary shows the evolution of his design sensibilities: it drops the labyrinth mapping aspect, and only a small portion of rooms is empty 
27. El Raja Key Archive. Rob J. Kuntz played through the entire old dungeon, and then became Co-DM and Co-Creator of the Expanded Dungeon; he published his old maps and map keys and still answers questions on blogs and at conventions. As part of the archive, he provides a timeline of adventures that helps  to separate which stories and hence dungeon features were part of the Old castle, and which of the Expanded castle. For the Expanded castle, this is the richest authentic source, unfortunately this is of less help for the original castle.
28. Statements by Rob Kuntz on the Pied Piper Forums.
29. Statements by Mike Mornard, on blogofholding (player of the Lessnard wizard from [5])
30. Statements by Jim Ward, one of the players in ENWorld Article Series
1. https://www.enworld.org/threads/gary-gygax-things.669413/
2. https://www.enworld.org/threads/gaming-with-gary-gygax.672277/
3. https://www.enworld.org/threads/the-origin-of-monty-haul.666872/
4. https://www.enworld.org/threads/james-m-ward-meeting-gary-gygax-and-learning-d-d.666226/
5. https://www.enworld.org/threads/elf-stranded-on-the-warden-a-short-gary-gygax-story.666515/
31. Reddit Discussion thread by Greyhawk Castle Enthusiasts who talked to the original players
32. The "extraplanar" side levels published as independent modules (EX1, EX2, WG6). They were for high level play, and are not mentioned in the list of side levels for the original dungeon, but [30.4] mentions that in July 1974 “You come upon three doors and each one is a bit strange,” Gary described. “The left one has the picture of an island in the middle of the door (it was the Isle of the Ape in playtest). The middle door has the picture of a walrus on a beach. The right one has a picture of an odd looking humanoid with a strange cap and in its hand is a strange crossbow pistol.” -- this was already in the expanded castle. The group was only level 3-4, so WG6 (which is for level 18 or such) must have been a lower level version - or deadly.
33. Swords and Sorcery in Wargaming, Wargamers Digest Vol 1 No 7, May 1974
34. Paul Stromberg Q&A on Reddit, 2019. "I have unearthed the original castle manuscript of 22 levels. Also, the larger, expanded castle of 62 levels is intact and well secured by Gary's widow, Gail Gygax. Additionally, there are over a dozen alternate levels that were used to change out levels depending on who was playing. In total nearly 100 levels of the castle exist with some 300 pages of keys"
35. Rob Kuntz Article Series on ENWorld about the Lake Geneva Campaign on Dragonsfoot
36. Gamasutra Interview with Gary
37. Discussion of GC Level Structure on Dragonfoot forums
38. Pied Piper Forums Tapatalk snapshot of discussions with Gary Gygax, Rob Kuntz
39. Mike Mornard interview on GROGTALK
40. Rob Kuntz Lake Geneva Original Campaign Blog posts
41. Rob Kuntz Lord of the Green Dragons Blog posts
42. ODD74 proboard forum disuscussions
1. Old Castle Greyhawk thread
2. Pieces of Old Castle Greyhawk thread
3. Lake Geneva Gaming Group thread
4. Just what do we know... about pre AD&D Greyhawk thread
5. Gygax and Clark Asthon Smith tread
6. Megarry's Copy of the Great Kingdom Map thread
7. Gygax OD&D vs Kuntz OD&D thread
43. Knights and Knaves Alehouse forum 
44. The Acaeum forums (a site cataloguing old D&D publications and their estimated collectors value)
45. Jack Vance and the D&D Game article by Gary for Profantasy Excellent Prismatic Spray #2.
46. Gygax Letter in Alarums & Excursions #15
47. Interview of Gary Gygax by C.A. Sacco. Jon Peterson comments that TSR was making losses in early '83 and Gary had signed on all the debts he claims to have "discovererd" during his return in the interview, here. Gary likewise ridicules Dave Arneson's invention of the format, the pages he sent that were incorporated to D&D, so this is a rather self-serving presentiation of the story.
48. Greytalk mailing list archive of posts including Gary Q&As

Allan Gohe has collected most sources on his blog. Allan's site is very comprehensive, covering both the Old and the Expanded castle. My interest as a hobby game archaeologist is more modest, mainly in the Old Greyhawk Castle. 

The earliest published adventures and rulebooks also provide clues on how the dungeon looked like.

Not a source: the Gord aspects were not intended to represent CG, because when I was working on CZ with Gary, I asked him about this. He told me that they were just tales written for entertainment purposes. [Ghul / R. Talsorian post]

Source Categories

The original maps of the dungeon and the associate keys still exist and would be the ultimate source, but the Gygax estate has not released them and may never do so. In the meantime, grognards are trying to reconstruct what can be reconstructed from these other sources from the period.

Period Materials contemporary or close in time to the creation 

• Rule Books (OD&D, Supplements - especially Supplement I, Dungeon Geomorphs), to a lesser extend DMG, Supplement II-IV
• Published Adventures / Materials (Lost Caverns especially the original version, EX1, EX2), to a lesser extend B1, B2, WG5, WG6, Tomb of Horrors again especially the orginal version, Expedition to the Barrier Peaks; Dave Arnesons First Fantasy Campaign Blackmoor Dungeons, Dave Megarry's Dungeon Game, DA3 City of the Gods in which Gary and Rob adventured
• Published articles (How to set up your Dungeons & Dragons Campaign, Hints for D&D Judges, Swords & Sorcery in Wargaming, Gygax Letter to A&E15)
• Published Stories (Magicians Ring, Expedition to the Black Reservoir)
• Unpublished materials (Dalhun Manuscript, Mornard Fragments, Notes sent to Gary by Dave, Letters) 
• Convention materials: If your are wondering what D&D is all about... Leaflet 
• Statements from Paul Stromberg with access to the materials

Later materials from play using the original dungeon maps

• The famous photographs of Gary with the original level 1 key and map, and level 3 map
• Play reports from convention games Gary ran using the original castle (EN World Game, WinterCon Game, Home Campaign)

The bulk of the material back then was improvised on the spot, and never written down, so even if we had them, these original documents would only provide a partial picture. We can complement them with sources from the memory of those that were present and involved. 

Memories from Gary and the original players that have been recorded  in Interviews, Q&As, Correspondence, Blog and forum  posts, Articles. 

And of course, we could still ask those still alive, considering it may be hard to remember details from a game 50 years ago. As of 2021, these include prominently (and still active on message boards)

• Robert J Kuntz
• Terry Kuntz
• Ernest "Ernie" Gygax
• Dave Mornard

Also old time players in the extended castle and later campaign

• Jim Ward
• Lucion "Luke" Gygax
• Tim Kask
• Frank Metzner