Worldbuilding through oneshots is exactly what says on the tin – its a technique where you play a one session game (a oneshot) and use that as the source material to create or expand on the setting for your game!

By sharing the creation of your world with your players it can give you ideas you’d never have thought of, twist your game world in utterly unexpected ways, and leave you scratching your head trying to tie it all together! I’ve had it go well, go badly, and (more often than not) go outright bizarrely.

Three gnomes playing a game at a table. Each gnome has a speech bubble with a picture illustrating what they are discussing. The first has a person riding a chicken, the second has two people fighting a dinosaur, the third has three stickmen holding swords.

That’s all well and good, but how do I go about doing it?

The easiest way is gather a few rough ideas for your oneshot. I’d suggest sitting down with your players as part of a session zero, explain the concept and see what interests them. Next, set the oneshot an unspecified time before your main game. (Remember this – it’s handy later!) Pick the system you want to use for the oneshot and run it!

After you’ve played the game, the story you told becomes the inspiration and basis for the world your campaign is set in. Plan your campaign as you normally would, but use the oneshot as the source material.

Ok, so why might you want to start a campaign like this?

Oh my gosh! Where do I start! Well for starters it’s an easy way to introduce players to the game world. Instead of having reams of exposition (which may or may not ever come up) they get to play out the important historical events! You’re far more likely to remember the cause of the civil war if you played the character who assassinated the king! Even before you’ve started the main game it gives players a reason to be invested in the lore. Also it adds some fun context – saying its illegal to go within two meters of the queen is easily forgotten. Saying its illegal “Because of your previous character’s actions” adds some interest and you’re guaranteed a smug smile from your players!

The other major boon is sharing the work of worldbuilding – especially if you use a GM-less system. Instead of the world being your sole creation, your whole game group is putting their heads together to create it. It adds a lot of variety and the GM can be just as surprised by the outcome as any other player! Once that’s done you cherry pick the interesting details and turn it into a campaign. Another advantage here is you can see what sparks the players’ interest. Perhaps a player gets fascinated by the heraldry or is increasingly intrigued by the flora and fauna.

Can you do this after you’ve started the campaign?

Of course! You can pop a oneshot session in at any point during your campaign. I often use it as a way of introducing a new location at the beginning of an arc.

It can also be useful as a tool to show what is happening while the main player characters are elsewhere – for example, setting your oneshot in the PCs home base, or taking on the roles of the evil overlord’s underlings. Plus it’s a good way to introduce new plots, show a different perspective on the world, and even foreshadow events that the player characters aren’t yet aware of.

However, my favourite use is as a way of visiting the past. If the player characters are researching something that happened a hundred years ago, why not switch to a oneshot and play to find out what really happened!

You seem to be pretty keen on shoving oneshots into your game, are there any downsides?

Much as I love using this technique, there are definitely some drawbacks. For starters it takes time. You’ve got to weigh up the worth of sacrificing a whole session to devote to the oneshot. It can also mean more prep time for the GM out of game.

Hang on, I thought you said it made it less work

…I did, didn’t I. OK, so there is less work upfront, however this technique does require some work in order to transform the oneshot into a broader setting. You have to gather all the details together and try to work out how they can mesh together to make a compelling narrative. Plus setting up the oneshot requires some prep in itself! (Even a zero-prep game requires learning and organising.)

On top of that, sometimes the material you end up with really doesn’t fit the game you want to run. For example sometimes what sparks your players’ imagination is ‘flatulent bunnies’ and spirals from there… leaving little source material beyond pungent rabbit puns… (If you haven’t already guessed, this happened to me.) Trying to turn that source material into a coherent world can take some effort!

A person looking at a grumpy rabbit with stink lines. The person is saying "How is this going to work"

.Wait what happened with the Flatulent rabbits!?

When the people demand bunnies and fart jokes, sometimes you have to give in and go with it.

However, remember I said your oneshot should be set an unspecified time before your main game? That’s where it becomes handy. The details that carry over are different if the oneshot happened six months before the main campaign vs. sixty or even six hundred year before.

You can use the time difference to control how similar the campaign is to the world of the oneshot. However it is still important to acknowledge your players’ ideas – their investment in the world comes from including what they have created.

The rabbit example can be used in a variety of ways without derailing the game. You could make the evil villain responsible for the near extinction of the rabbit population (Their favourite pastime is bunny hunting!) This becomes a sneaky way to focus the players’ ire – the players in-joke is under threat! A milder use is to illustrate how times have changed – what were once green fields are now sprawling slums that don’t smell much better than the previous wildlife! Or you can simply keep it as a joke in the background. Sometimes things can just be part of the scenery.

That sounds like you’re just ignoring the worldbuilding game and writing your own world

Maybe a little, but the key elements were all drawn from the oneshot – although the oneshot focused on something absurd, locations & ideas can still be drawn from it. It still draws on the players’ investment & gives you an idea of what they will enjoy!

I’m not convinced.

Thats fair. You have good and bad days, sometimes things don’t work as well as you hoped. The rabbit example wasn’t my most successful worldbuilding game, but we still had fun & I managed to pull some decent source material from it.

On that note are there any times you’d suggest avoiding this?

No. It’s an amazing technique and should be used at every available opportunity.

I think you may be biased.


Seriously though…

Ok. There are a few occasions where I would advise against worldbuilding through oneshots. The most important consideration is, are your players interested? You can you can try to sell it to them, but if the idea doesn’t appeal, it won’t work.

I’d also advise against using this technique towards the end of a campaign, too. At the end of a campaign you are working on resolutions and tying up loose threads, not looking to add new hooks and ideas!

Lastly, use caution when approaching key parts of your story. Suppose your plot is centred around a civil war sparked by the assassination of a monarch. If you do a oneshot covering the assassination, there is a chance the players may decide to save the monarch! Generally you’ll find a way around it – the king could be in hiding and everyone thinks he’s dead etc – It could be a fun twist in the story. However if there are too many implications to explain away (prophecies, magic etc. etc.) it can put you in an awkward position. Unless you’re happy for a detail to be changed, its easier not to tempt the fates.

That’s fair… Any other tips?

Everything will work much better if you are upfront with your players– be clear it’s a oneshot, be clear that it will become the background to your campaign.

If you want to focus on worldbuilding, it usually works better if the characters in the oneshot are different to those in the main game – it leaves your players open to make more interesting choices without having to worry about the personal consequences. On the other hand it can also be a fun tool for exploring characters’ backstories too.

I may try it out…

You totally should! It’s a fun technique that can exercise your GMing ability and make your campaign as surprising for you as it is for your players!