Using Orbital Crypt’s 18-Slot Inventory

Orbital Crypt recently described an 18-slot inventory system “inspired by the old word” to track resources in their campaigns. In the past, I wrote about the place component of campaigns using point-crawls and recently wrote about the time component using a campaign tracker.

I read Orbital Crypt’s post about the 18-slot inventory just as I was contemplating what other components that I could make explicit for campaigns. Though the components would likely vary depending on the type of game you want to run, tracking resources is a common enough component that it warrants further discussion.

I liked the system described by Orbital Crypt and I immediately thought of how I might use it in my campaigns that require meaningful resource tracking.

What is a slot-based inventory system?

Tracking resources has been a cornerstone of roleplaying systems since the early editions of Dungeons and Dragons in which the players were required to carry treasure from the dungeon to advance but also required to bring adventuring gear to be better equipped.

Over the years, as knowledge becomes lost and the way we collectively view roleplaying games changes, some have cried out about the bookkeeping required to track these resources.

There have been some that have experimented with alternative methods for tracking resources and encumbrance:

  • Justin Alexander of the Alexandrian described such a system by simplifying the math and using heavily structured character sheets over a decade ago in his post series: “Encumbrance by Stone
  • A more recent development was a slot-based system described by Benjamin Milton popularised in his system “Knave“.

A slot-based system allows for a more visual experience of tracking resources akin to inventory systems in video games such as Diablo or World of Warcraft. Some items take up multiple slots and other items such as coins can be stacked into a single slot.

It reduces the mathematics to a simple question: “How many slots do you have left?”

Effectively, it focuses on the intention underpinning the tracking of resources and encumbrance: Constraining the players and forcing them to make hard decisions about what they can carry.

Orbital Crypt’s 18-Slot Inventory System

Orbital Crypt described a system for a slot-based inventory that considered containers an adventurer may carry such as backpacks, pouches, and satchels.

These containers were ordered into a hierarchy that was somewhat mismatched for how I might use it. This was later acknowledged in the blog post; however, it was presented as such:

  1. Quick items: This was composed of two slots and were items that could be accessed readily in the heat of the moment.
  2. Backpack: This was composed of six slots and represented a large bag strapped to an adventurer.
  3. Satchel 1/2: Each satchel was composed of two slots and represent smaller bags strapped to an adventurer.
  4. Pouch 1/2: Each satchel was composed of one slot and represent tiny bags attached to an adventurer.
  5. Worn/Carried: This was composed of four slots and represented the items currently being held or equipped by an adventurer. It was noted that other slots could be used to represent this.
  6. Triangle/Square: Two more spaces were provided each marked by either a triangle or a square. It was a large space that could be used store many small, trivial items. To use this, one of the aforementioned slots had to be marked with the corresponding shape.

There were some other elements to the system such as a list of items not included that described how many slots each required, how each slot was numbered, and that each slot can contain 100 coins. Additionally, there were some later musings about how to expand the system.

However, my focus is on how I may reorder the container hierarchy and integrate a rule from Troika! to govern access to items in battle or other moments of stress.

Using the 18-Slot Inventory System

Here are the following changes I have made to the inventory system to suit my needs during a campaign:

  • Renamed worn/carried to equipped.
  • Restructured the hierarchy of the containers as such: Quick, Equipped, Pouch, Satchel, and Backpack.
  • Removed the numbering on quick and equipped, though the number of slots remains the same.
  • The slots of pouches, satchels, and backpacks remain the same but are numbered from one to twelve.
  • Implemented the “Retrieve and Item” mechanic from Troika! to provide a rule which governs what players can access in the heat of the moment and encourage thought about where to store items.

A player can always access items in their quick or equipped slots. If a player wishes to access an item in any numbered slot during a time of duress such as combat, they must roll 1d12. The player can then use their action to gain access to any item corresponding to the number they rolled or less.

Additionally, I may use a modifier on that roll depending on the system and the context of the situation.

All these changes lead to the inventory system to look something like this image below:

A modified 18-slot inventory system that reorders the hierarchy of containers as described in Orbital Crypt’s blog post.

Closing Thoughts

Inventory slots can be a great visual tool for helping players care about their resources and how they organise them without slowing down the pace of a game through extraneous mechanics.

The idea is not to be hyper realistic, instead it is used to encourage meaningful choice for the players when they are constrained by what they can carry.

The reordering of the containers more logically fits with the implementation of the Troika! rule for retrieving items during combat. Additionally, this will support the intention behind the mechanics for caring about encumbrance and resource tracking.