The Museum of HP Calculators

HP Articles Forum

[Return to the Index ]
[ Previous | Next ]

The Caves - Reloaded

Posted by Frido Bohn on 6 May 2010, 5:03 a.m.

The Caves is a classic HP41-game designed by James Surber and published in the Games II volume of the Users' Library Solution. Its listing can be found at this site.

Game Summary
This is a typical maze game with 67 interconnected caves. The main goal is to collect the treasures to an amount of 1200 points. The caves contain also several hazards and some gadgets.
The game starts asking for a seed number. Thereof the items of the game will be distributed across all caves. Each seed number will generate a specific distribution pattern which can be restored using the same number again in a later game.
Some seconds after entering the seed number, you enter the game in Cave 0 in user mode and will be informed whether some hazards exist in the adjacent caves or not, but you will not be informed in what particular cave the hazard is. The only means to get more information about the caves is a wizard (hear voice) who will tell you something about the five lower and upper caves as seen from his cave. Otherwise you have to adventure the next caves by luck and logical deductions.
Each cave is connected to three other caves, with two exceptions, with only two neighbouring caves. The leftmost number in the display is followed by an "*", and marks the cave where you are just in. The other three comma-separated numbers display the adjacent caves. By entering the respective cave number you will get access to that cave. There are also stairs and forks. Stairs will give you the option to go up- [Key F] or downstairs [Key G] to a random lower- or higher-numbered cave thus, you have no control where you may end. The forks give you the option to go right [Key I] or left [Key H]. In this situation, the number of the caves will be shown to you, thus giving you a bit more control. Finally, you may go backwards to the cave you just left [Key J].

Your basic equipment consists of five tools (knife, water, gloves, lamp and keys) and may be expanded by a wand and a cape if you are lucky to enter the respective caves. Part of the equipment will defend you against dragons (cape), fire (water), trolls (knife), dark caves (lamp) or grant you access through locked doors (keys). Other equipment is useful to collect the treasures, i.e. gloves for gold (AU) and silver (AG), as well as for rubies and silk which are locked in chests for which the keys are to be used.
Some hazards like holes (draft) and a kind of waterfalls (splash) irrevocably kick you out of the game. Each time, you enter a new cave you will be informed about the content of the neighbouring caves, with few exceptions (trolls, fire, locked doors, web, dark cave, small cave). Most of them can be handled with the standard equipment. But standard equipment may be lost if you enter caves containing bats (hear squeaks). In such a case you may conjure them back if you use the wand. The wand itself must be found first in a cave, and will work twice only after each visit to that cave. Likewise with the cape. It is useful to hide oneself when entering caves containing dragons (smell dragon), but it can be lost if you get into small caves. Of course you can adventure yourself without some standard equipment but this could be risky as you might enter a cave with a troll without warning and without your knife which finally would throw you off the game. A cave with fire would burn you if you have no water, and a cave with a web or a locked door would deny you the access if you have no knife to cut the web or keys to open the door.
Another gadget to be found in a cave is the magic word. Upon using it will get you out off the maze in healthy conditions. The other way of a healthy escape is the use of an exit-cave (see light).
I hope this brief description gave you some clue about the aim of the game. As stated above, the game is introduced in detail in the Games II Users' Library Solution book.

System Requirements
For an HP41 it is challenging because all 319 registers are needed. Thus, it can only be handled by a 41C with full memory, or of course by the CV or CX. But in either configuration, you will not have enough room for any other programs. It is recommended to use a fresh (memory lost) system and start with zero registers (SIZE 000) in order to accommodate the program first. After packing, you will have to give the game 76 registers (SIZE 076) in order to start it properly. For the best performance I advice to delete the key assignments before starting the game to have full access to the controls of the game which uses labels A to J.

User Requirements
The game is not only challenging for the HP41. This applies also to oneself. When I started to play the game some years ago, I found that my mnemonic capabilities where driven to its limits. First, it is difficult to understand the system of the interconnections between the caves. Second, you have to deduce where the hazards might be, as you only will get hints about their rough location.
Therefore, I recently had the idea to prepare a map which will ease the path through the cave-system. If printed out, you may use it for your notes. The location of hazards can be nailed if you by-pass the suspected cave through another cave in the maze. The map is also good to annotate the hints of the wizards.
Additionally, I gave a basic scheme of the hazards, its remedies, the HP41-key assignments, and scores of the treasures. The lines between the caves display their interconnections. Do not be confused if they are dash-dotted or full, this was only done to mark the correct path. The paths from Cave 7 to Cave 0, and from Cave 60 to Cave 61 are one-way only. On the right lower edge, you will find "Seed" where you can annotate the seed number you used at the initiation of the maze. Very useful, if you want to re-challenge that nasty dragon which kicked you off the game.
A tip: if you want to get rid of the sound, clear flag 26 [CF 26].

Although a game of the computer stone-age it is quite fun to play and demands the use of neurons which usually are left in stand-by. All you need is an HP41, a sheet of paper and a pencil. I may quote my 8 year old son who stated that the game is "somewhat more challenging" than most of his hand held console programs.

Note: The CAVES map may be obtained directly from me (fridboh at

Edited: 30 May 2012, 11:40 a.m.


[ Return to the Message Index ]

Go back to the main exhibit hall