Charted Space, the Original Traveller Universe is big. It is pretty too big for most practical purposes. There are a few ways to approach this. The most common is to find places that are more interesting for games to take place in (I have some suggestions for interesting places my intro to Classic Traveller post). One can also just roll up your own setting, which is the assumption in the original books. This post if going to talk about a few considerations of how to shrink the whole OTU setting down to something more manageable.

The official map of Charted Space is 16 by 8 sectors. Each of these sectors contains 16 subsectors. Each of the squares in the following map is a sector.

A single sector is called out on page 80 of the Traveller Book as being a sensible upper limit for a full campaign:

Sixteen subsectors (arranged in four rows of four subsectors each) form a sector, probably the largest size practical for a continuing Traveller campaign.

So by the guidelines of at least the earlier books, the entirety of Charted Space is too big.

This being too big is certainly borne out by my own reviewing of the OTU. The main issue with it being as big as it is is simple: the fun stuff is on the frontiers. There are multiple sectors in the imperial core that are largely interchangeable, because the only thing in them are system controlled by the 3I. (This is one reason that I actually like the concept of the Rebellion from The New Era and Hard Times - suddenly there are frontiers everywhere.) In addition, there is not really any good way to have something happen on a particular area if it is far away from the area chosen to start the game. It will be difficult to have the Fifth Frontier War between the Zhodani and the 3I in the Spinward Marches and a flare-up in tensions between the 3I and the Solomani Confederation and a renewed 3I effort to push into the Julian Protectorate, simply because the travel time between those locations is going to necessitate large time skips or a lot of travel.

It also means that a given campaign will be dominated by the alien in that area. If there is a desire to include all of the major species in Charted Space (Humaniti (Zhodani, Solomani, Vilani), Aslan, Vargr, Hivers, K’kree, Droyne) in a single campaign then either major time skips or a new set of PCs can be created in different areas.

Therefore, this post is going to focus largely on considerations for shrinking the OTU down to something more playable than 128 sectors (2048 subsectors) - how much, and what trade-offs doing so might have.

Single Subsector

We will start at the bottom end of the scale, with a single subsector, consisting of 8 × 10 hexes. This is a very good size for starting a campaign off, since you do not need to make many systems and you can easily expand it as your campaign continues.

While it is technically possible to shrink the OTU down to this size, a subsector is so small that honestly it is probably just better to make your own - it will likely be more fun to play in. That said, a single subsector with the centre being an 3I surrounded by other polities can work. You will just end up with a 3I that is a handful of systems at best, and you will not get the chance to include many of the famous systems from places like the Spinward Marches.

Single Sector

So what about the size recommended by Marc Miller? There are many ways to do this, depending on what you are looking for.

Major Tension

One lens that I find particularly helpful is to consider what the major tension in each subsector is. As a good example, the OTU’s Spinward Marches has a showdown between the Zhodani Consulate and the Third Imperium with a scattering of smaller polities. So the question here is how the Zhodani and the 3I deal with exerting control of the neutrals between them. Given that we have less space available, each subsector should have some similar question that can be used to drag PCs into what is going on.

So, looking at regions of Charted Space, what are some obvious areas of friction? Ideally, we can come up with 16, each of which could be turned into a single subsector. I did not quite get to that, but this is most of a sector:

1. The Spinward Marches: 3I vs Zhodani with some smaller polities, notably the Sword Worlds and Darrians.
2. Corridor: The 3I dealing with Vargr raids, as well as internal Vargr squabbling.
3. Meshan/Mendan/Amundakan: The 3I dealing with the Julian Protectorate, who are also dealing with the Vargr and internal politics for themselves.
4. Solomani Rim: The 3I vs the breakaway Solomani Confederation who are looking to reclaim Sol.
5. Core: The appeal here is mostly related to high-level politicking on Capital, but you could seed in a potential Rebellion scenario by putting Ilelish and Vland in the same subsector or at least in a position to act as a counterweight to Capital’s supremacy. PCs can then engage in internal empire politics with those as the major poles.
6. Reaver’s Deep: The 3I facing off against the Aslan and the Solomani over some neutral worlds between them.
7. Spica: The Solomani and the Hivers dealing with each other.
8. Trojan Reach: The 3I and the Aslan squabbling over neutrals.
9. Glimmerdrift Reaches/Hinterworlds: The 3I pushing into smaller neutral territories.

A recurring theme in the above suggestions are 3I and someone else squabbling over neutrals - most of the adventure is on the frontiers!

Published Adventures

Another thing to possibly consider is the location of adventures in a given place. Doing this is going to drive things towards areas with more attention, of course. This makes places like the Spinward Marches much more prominent compared to deep inside the 3I or Zhodani territory. If you want to be able to use previously published content though, then you are sort of limited to places that have adventures published.

The aforementioned tendency of frontiers being more interesting also has the strange effect of making places like the Spinward Marches more prominent than they otherwise would. The main thing to consider here is that this can help you choose what systems to keep from an existing sector: lean towards the ones with published adventures and material.

Intended Audience

The purpose of making a single sector should also be kept in mind, and this largely comes down to the intended audience. If one is preparing a sector for themselves, then it may be simppler to just make a new one and adapt any published adventures to that new sector.

If the intent is to share the sector for other people then my feelings are that you want areas with a simply-understood central high-level tension for players to get their teeth into. At the same time, ideally you keep systems that have published adventures, but put them closer together or otherwise make them available without needing the original maps.

Single Domain

A domain is a subdivision used by the 3I and is nominally a four-sector square of space. This is actually a fairly good size for a smaller Charted Space, since it give a bit more room to breathe, while still being fairly contained. This is an especially appealing option if you are using ships with higher jump ratings (for example, many of the vessels in the core book have J3 - the subsidised liner, the mercenary cruiser and close escort).

Other Sizes

The above are all conventions, however long in the tooth they may be. Just because Traveller originally said that subsectors are 8 × 10 parsecs and sectors are 4 × 4 subsectors is no reason to stick to it blindly, especially when making new ones on paper. It becomes more difficult using digital tools, because almost all of the digital tools assume 8 × 10 parsec subsectors.

One worthwhile software exception is sectorswithoutnumber.com, which is intended to support Stars Without Number. This allows the creation of maps for SWN with between 5 and 20 parsecs in each direction. Stick a few of these together and you can easily make a slightly larger sector. If you are doing things on paper, of course, then there are no such limits, and you can just scale hexpaper as desired to make your sector. One good place for this is Incompetech, which allows you to specify your own size.

Final Considerations

Ultimately, shrinking things down is worthwhile. How much and what you want to shrink will vary a little on what you want to do, but the ideal size for me is probably about a sector, maybe a little bigger without hitting a full domain.

The next post will showcase a couple of examples of how things might be shrunk down with some thoughts about them, and the one after that will have a full sector that can be used, since one has to pay the Joesky Tax at some point.