Old Greyhawk Castle Level 1

This is the original level one from Old Castle Greyhawk, the only level for which we have both the map an the key from Gary's notes. The map is the original 1972 one. Here is a cleaned up view. 

People with better eyes than me decoded the key, which is not the original one, but likely close:

LEVEL 1 THE VAULTS

1. 9-16 KOBOLDS – dust covered silver mirror 750 CP[?]
2. 7-12 GOBLINS – 10 GP /
3. 3-12 GIANT RATS – no treasure (in room potion strength)
4. 10-16 BANDITS, LEADER WARRIOR - +1 shield, potion und. cont., 1,000 GP 
5. 5-8 GIANT CENTIPEDE NEST –
6. 2-3 HOBGOBLINS – Battle axe +1, gem 200-800 GP
7. 1 GIANT BLACK WIDOW / SKELETON IN PLATE AR – 50 GP on floor
8. – IRON[?] CHEST, EMPTY - false bottom[?], needle trap, 6 gems c 200 ea
9. 3-7 ORCS - chest with 8 flasks oil, 30 SP + 8 GP /
10. – WATER SEEPAGE – drink!
11. 1 GIANT CONSTRICTOR – Gems inside (1-4) or nothing 50/50[?]
12. – RUSTLING CORRIDOR – no bats
13. 2-5 SKELETONS (pile of bones) – 1 piece of jewelry [in pile?] (d10 x 300)
14. 1-2 GIANT BATS – no treasure – RUSTLING [more text unreadable, may continue line above]
15. 1 GIANT STINK BEETLE – 2 attack in 5’ r. – nothing/10-100 SP + 1-10 GP
16. 3 BERSERKERS – R. of Prot., 20-40 GP each, Idol with curse (-1/[+3?]/[d in or dia?])
17. 1 SEER (Chaotic) – LIGHT, CH.PER. – +1 dagger, spell books, 1-20 GP 
18. 1 EVIL ADEPT + 1 GNOLL Gd. CAUSE LT. WOUND.– staff of healing (6 [?] chg) 
X-circle [red] PIT – 10’ deep – TRAP
O-circle [green] TRANSPORTER

A warrior is a level 2 fighter (called fighting-man in OD&D), a seer a level 2 wizard (called magic-user), an adept is a level 2 cleric. Based on the stories of the original adventures, the centipede nest should originally have been near the entrance. 

The reason for the unused space on the right border is that there are 3-ring binder holes there. While the maps were in plastic sleeves at the con, the original was likely put in a three ring binder with the map on the left, the key on the right, for play.

Here is Matt Bogen's photo of Gary running the game for ENWorld moderators at GenCon 2007 that provided the source for all this:

The original map from the photo, stretched square and magnified:

Gary described he originally created the level as: A simple maze of rooms and corridors, for none of the participants had ever played such a game before. [3]

Monsters & Treasure

The key is not the original one, as Gary described in several instances a chest with thousands of copper pieces that the kobolds held as treasure in the first play sessions, and that chest is not listed here.

Several rooms show a 1 for kobolds or a 2 for goblins. The treasures listed for those keys are in some cases specific (like a silver mirror for the kobolds), so it could be that these groups were spread over several rooms. However, there are at least 6 rooms with a 2, that would just leave about one goblin per room. It seems more likely that the numbers indicated the area controlled by the monster group, or that each of these rooms had the allotment of monsters, and only one of them had the treasure. There is an  analysis that tries to square the XP of this key with the OD&D guidelines.

When he played this level later at conventions, his original 14 kobolds killed several groups of players, getting stronger or more numerous each time, which he explained in a post. This resulted in the elite kobolds described in Castle Zagyg (who had the shaman he contemplated adding in that post). The original kobolds were just plain old kobolds. 

In the home campaign from 2004/5 that used this map PCs were already level three or four, and the encounters were: 9 orcs with chieftain; bandits were level 2 fighters, with a level 4 leader and had 3,000 g.p., 2 potions and a sword +1; the evil priest had two gnoll guards; the giant rats a human keeper; there were multiple giant black widows, and the armor was +1, there were multiple giant stink bugs; additional treasure of 10 +1 arrows, a +1 dagger and 8 gems base 100 g.p, and the kobolds were much stonger and numerous than indicated here.  

All of this just shows how the actual dungeon was somewhat fluid and he adjusted the dungeon difficulty, treasure, number and strength of monsters a bit for PC actions or level [1, 7]. 

Traps

The map does indicate traps. What were these traps?

A couple open pits (in corridors), useful in combination with doors---entering from the non-pit side PCs may fall in, while the pit makes the door difficult to use from the pit side. [16] 

This is contradicted by [13], where one of the players drops into a covered 10' pit behind a door. I believe that Gygax used open pits in the very beginning in 1972, or with new and less experienced players, and used the more challenging covered ones with more experienced players. As he advises in [7]: adjust the difficulty of encounters accordingly. Some monsters can have higher HP or HD, while others might be more numerous [...] It is your job as Castle Keeper to appropriately challenge your players. 

The group that he ran was level 2, as he mentions in his own recounting of the trip: dungeon crawl in my original Greyhawk dungeons for a half-dozen of the Esteemed EN World Moderators.  [...] Each of the six created 2nd level PCs and managed to survive the adventure. According to his dungeon stocking advise in OD&D there is no question that a player’s character could easily be killed by falling into a pit thirty feet deep or into a shallow pit filled with poisoned spikes, and this is quite undesirable in most instances. 

Random Encounters

The encounter key above did not provide information on wandering monsters. It is very likely that the ones listed for random dungeon stocking in OD&D and the Greyhawk Supplement came from the ones used in the Castle, and best to use would probably be the one from Greyhawk. 

In the home campaign from 2004/5 play reports, there were wandering monsters: ghouls, and groups of up to 10 skeletons. [12] In the EN world game, the level 2 players encountered a gelatinous cube as a wandering monster (likely attracted by the noise of their treasure cart). All of them fit these tables. Ghouls would typically be a level 2 encounter, but the players where at higher level already (and the stocking method also allows for picking a deeper level denizen.)

Stairs

According to ENWorld Game, there were stairs down in each corner. This would mean the stairs in the SE would go up, not down, and the grey angle in the NE are stairs, too. 

Changing the level

Here is the map the players from the EN world session created.

This map is from the same session, as the map on the photo above, but it differs at several points, in ways that cannot all just be mapping errors: the entrance stairs and room are different, doors differ, the area north of the split room near their entrance differs, the rooms and archway location near the stink bug differ, and most extremely, the stairs down they found are definitely not on Gary's map.

All this just goes to show that Gary used the map and key for the most part to trigger his imagination and provide framework, while he made up a lot on the fly. 

Is this really the original level one map? What about the one from Castle Zagyg?

This map, not the one from Castly Zagyg is the original 1972 1st level. Gary says so himself in his report on the game. He also describes the original level like this: It was a level that had lots of corridors and rooms, few squares penciled in to indicate solid stone. There were, however, only about 20 encounters on it", and in a forum post stated I have run OD&D games every year at several cons for the last five or so years. I start them at 2nd level [the PCs, not the dungeon level, ed.] and use the old dungeon levels. [17]  

The map in Zagyg closely fits his description of the map that was created for new Level One of the Expanded Dungeon: I drew a new first level that could accommodate both bands of fledgling adventurers and the initiated. Four separate descent areas were created with designations by the cardinal directions. Each had multiple flights of stairways leading lower, some ending several levels farther down. Three were "guarded" by dungeon denizens -- elves, dwarves, a very large and strong ogre. [15]

[Benoist] reports in the K&K Alehouse forum that Ernest Gygax, who played in the original campaign, also remembers the map to look like this, not like the one from Castle Zagyg: I showed the maps to Ernest, both this one, and the map of level 3. He told me these certainly look like the original maps of Castle version 1, back when Rob was a player, not a DM.  I showed Ernie [...], the Castle Zagyg map [...], and the level 1 map [above] together, in that order. His answer was [...] the bottom map is the way I remember the 1st level.

How does this play?

I have not played it, but the fact that everyone, including Gary dropped this style of labyrinthine maps and mapping challenges likely means it was less fun than a map with higher occupancy and fewer rooms. You were wandering around wasting time to get to the good parts. 

Here is a quote from T. Foster, about how playing such a dungeon feels:

The long hallways and winding, circuitous, and overlapping routes (and occasional dead-ends), the clustered nests of small rooms, the low occupancy rate (with the vast majority of rooms empty or only transiently occupied) -- all of these help create the "maze-like" atmosphere where the dungeon seems bigger and more complex than it actually is. Throw in a couple teleporters, one-way doors, and sliding walls (all of which are probably there, the resolution of the pic just isn't high enough to pick them up) and this one-sheet 5x5-grid dungeon level with probably about 200 rooms and 18 keyed encounters will, in play, feel almost infinitely large, with dozens or even hundreds of options facing the players. Which means that when they do come across something distinctive and unusual (i.e. one of those 18 key encounters) they'll really feel like they've accomplished something (and then will start wondering how they're going to find their way back to the surface, and how they're ever going to find this room again -- and suddenly the idea of players drawing a map begins to make a lot more sense :)).

If you've never run or played in this type of dungeon it has a feel that's completely different from a simpler, more straightforward layout that, even if it's large, is still easy for the players to grasp conceptually, and that makes them feel that it's only a matter of time (and patience) for them to have explored and mapped the entire place. In a dungeon like this you don't feel that way -- you always feel like you've barely scratched the surface of its possibilities.

[References: see Greyhawk References]