Without question, the GURPS rules are by far the most complex rules for any RPG I’ve tried. Though I’ve generally been fine with the complexity, it’s often offputting for both GMs and players alike – especially newer ones. GURPS has its advantages though – it’s able to model just about anything with its rules. Not all rules are useful though, and many add complexity to the game. This is why GURPS is described as a toolkit – you should pick and choose the rules you want to use for a given game.

“Picking and choosing” the rules for a game is no easy feat, given the monumentous amount of rules to the system. Making a “Celestar Ruleset” (i.e., the selection of rules best tailored to Celestar) is something I’ll need to do at some point, so I considered a few approaches:


My first idea was to start with Basic Set, and then write an “errata” of sorts – listing all the rules to be ignored, the rules to be changed, and the rules to be added from other books. It would probably take a format like this:

Use the full rules from Basic Set, with the following changes: 
--> "B420: Ignore the Bleeding and Accumulated Wounds rules".
--> "PU2: Characters may take any of the perks listed in this book, except..."
--> Etc.,

This would continue until everything was accounted for. A few moments of consideration automatically reject this idea – Basic Set totals to 576 pages, and every further supplement (e.g. Martial Arts, Ultra Tech, etc.) is another ~250 pages each. There are generally two outcomes to this – either:

  1. I have a massive, complex errata to “condense” the rules, or;
  2. I don’t make many adjustments, leading to a smaller errata but a massive ruleset.

Either way creates headaches for most players – option (1) requires constant cross-referencing, and many changes are bound to be missed, assumed, or misinterpreted. Option (2) fails to solve the problem I set out to fix. The more “lite” I want the rules to be, the more complex the errata has to be. I’d just be trading out one kind of complexity for another.

This issue arises from starting with a complete set of rules. To make a brief analogy, imagine it like building a house. It’s far easier to work on an empty plot of land than one with a skyscraper on it already.


The next option, naturally, is to do the opposite. Start with basically nothing, and work up from there, writing down the rules I am using. The “minimum foundation” to start from is the “three basic game mechanics” outlined under “Quick Start” (B8) – success rolls, reaction rolls, and damage rolls. This also comes with its own issues – if I did this, I’d have to make a list of every rule I was using, which is just as problematic. “Start small, go big” is just a bit too extreme.


A good “middle ground” does exist though – GURPS Lite (which can be downloaded for free from SJG here). The product description indicates it’s perfect for our use here – I’ve coloured the most important parts in red:

GURPS Lite […] covers the essentials of character creation, combat, success rolls, adventuring, and game mastering. […] [It helps] GMs bring new players into the game, without frightening them with the full GURPS Basic Set and a stack of worldbooks!”

Product description for GURPS Lite, available at

This follows a similar “foundational” approach to “start small, go big”, but the foundation is way more developed. This allows me to avoid the legwork of establishing very basic rules and features, and gives me something substantial to work off from. I’d start by assuming GURPS Lite, and any changes to that would be given in an errata (or, in the case of custom rules, written out). This reduces complexity significantly, and is likely the best method to keep the final result “everyone friendly”.


The entirety of GURPS Lite is 32 pages, and it’s far more digestible when compared to the bulky Basic Set, with 576(!) pages. A question arises though – what is the right amount of pages for an “everyone friendly” ruleset? To find this, I’m going to look at the core rules from one of, if not the most popular RPGs of all time, Dungeons and Dragons. It’s widely considered to be extremely friendly to all kinds of players, and for many people was their first foray into RPGs.

The Player’s Handbook contains a fair few of the core rules relevant to gameplay, and comes to a total of 316 pages. However, most people would suggest having more than this – the Dungeon Master’s Guide (320 pages), Monster Manual (352 pages), and Xanathar’s Guide to Everything (192 pages) are frequently recommended accompaniments. Taken together, they represent 1,180 pages of rules!

Of course, not every rule will be used at once in every game. The rules for sneak attack, for example, aren’t important if nobody plays a Rogue. In general, the rules for character-specific features (as well as for character creation) are largely unimportant when it comes to actual gameplay, unless they are specifically being used.

This thought can be applied to Basic Set too – for example, the Advantages and Disadvantages section cover 135 pages together (about 25% of the book). However, once they’ve been selected, players only need to remember the small handful of advantages that are actually relevant to their character, a set of rules that likely encompasses only two pages total. Further sections of the book can also be safely ignored – the rules for Psionics and Magic, which together make up 23 pages, aren’t important in Celestar, where those things don’t exist.

In fact, with GURPS, after character creation, the main bulk of the rules you need to know sits in the 103-page section between the start of the sucess rolls section, to the end of the age and aging section (a section which has questionable utility in most games). The rules outside of this either pertain to character creation, or rules more explicitly for Game Mastering (which we don’t count for fairness, as we aren’t including the Dungeon Master’s Guide in the D&D page count). We won’t include rules from other books (e.g., Martial Arts) in the same way we’re not including rules from Xanathar’s Guide to Everything.

When it comes to the Player’s Handbook, the rules important for play come between pages 173-205 (plus 3 pages for condition rules between pages 290-292) – a total of 36 pages. I’m not including the 83 pages of spells, or the rules for backgrounds, equipment, classes, races, and other character-specific options for fairness. All in all, the Player’s Handbook’s “crucial rules” section is only about 35% of Basic Set‘s crucial rules.

When it comes to GURPS Lite, when applying similar considerations, there are approximately only 14 pages of crucial rules. When it comes to making an adapted ruleset for Celestar, we’ll be pulling in a number of rules from Basic Set, so we can expect the “Celstar Ruleset” to be somewhere in the range of 14-103 pages. After accounting for duplicate rules (no need to explain success rolls twice) or sections we’re deliberately not including (e.g. Tactical Combat), we’re looking at a ruleset around 47 pages, likely less once further things are simplified and/or removed.

My aim with the “Celestar Ruleset” is to condense the rules down to 36 pages or less, to bring it into the ballpark of D&D and other popular “everyone friendly” RPGs. To do this, I’ll compare the rule as it appears in Basic Set with the rule as it appears in GURPS Lite, and I’ll decide whether the changes made in Basic Set are worth including (i.e., they either add to the game, make way more sense, and don’t add a horrendous level of complexity).

It’s also worth noting at this point that GURPS Lite won’t be a perfect fit – both were being worked on at the same time (both were released in early/mid 2004), so will naturally require some tweaking anyway. This quote explains it well:

Scott Haring revised GURPS Lite, Third Edition into GURPS Lite, Fourth Edition. I [Dr. Kromm] would like to think that he did a good job, too. Unfortunately, he had to operate in an information vacuum, because the GURPS Basic Set, Fourth Edition was a work in progress at the time, and he had very limited access to Pulver and me, who were of course busy revising the Basic Set.

Sean Punch (aka “Dr. Kromm“), GURPS Line Editor, from this post here on the SJG forums.

Some areas, of course, won’t require tweaking at all. The “Free Actions” rules (GL25, B363) are identical between both versions of the rules, for example.


Making a custom ruleset from the foundation of GURPS Lite is a bit of a murky area, copyright-wise. Largely, it depends entirely on how I go about doing it. Certainly, simply copying and pasting rules from Basic Set into a different PDF and then distributing it isn’t allowed (even if I’m not selling it), as per the text in GURPS Lite:

“You may not remove any part of [GURPS Lite]. You may not change or modify it, [and] you absolutely may not incorporate this game, or parts of it, into another product for distribution in any way.”

Small print, bottom of page 1 of GURPS Lite, Fourth Edition

For example, I can’t just take the “Move and Attack” maneuver from GURPS Lite and share it word-for-word in a different PDF called “Celestar Ruleset”. This isn’t to say I can’t have anything related to it at all – “game aid” documents like this essentially paraphrase the maneuver, keeping in the important stuff, and changing/omitting the excess. “Broadly explained” rules like this also exist, where the rules aren’t given much detail. Then there are wikis like this, which write out new rules in a GURPS-like format, or list changes to existing rules (like an errata).

In general, it seems that I’m not allowed to lift rules directly from existing published GURPS materials. If the changes are minor enough to the point where it could easily be covered by an errata, it should be written as an errata instead. I can, however, make “game aids” which list the rules in short-hand, or write custom rules in the “GURPS” wording, as long as I don’t the documents look like official GURPS books.


I’m going to start creating the Celestar ruleset, and I’ll talk about it in future posts. I don’t plan to start from one specific area in particular (e.g. from start to finish). This would be the more systematic approach, but I think it’d get tedious for me if I did it this way (rather than navigating it by interest). I do know a broad “roadmap” though.

  1. I’ll start with the rules in GURPS Lite first, and work out what needs to be tweaked and added to those.
  2. I’ll then look at rules that appear in Basic Set, but not GURPS Lite, and add those in.
  3. I’ll then look at rules from other books, like Martial Arts, and see what, if anything, from those should be added.

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