Unblocking On-Chain Games: Part Two — The 18xx Genre
This is Part Two of a series exploring constraints at the intersection of blockchains and games. The objects of inquiry are “crypto-native” or “on-chain” games, which maintain their game state trustlessly.
About me: I’m a core contributor to Alliance DAO, a startup accelerator and founder community. I’m a co-founder of @d_fdao (Dark Forest DAO), a group of on-chain game builders. I hold a PhD in Game Design.
The Context for 18xx
Francis Tresham was a brilliant, if oft forgotten, designer who pioneered the 4X genre and introduced the game pattern “technology trees.” Sid Meier’s Civilization (1991), despite its auteurist title, was actually an adaptation of Tresham’s board game, Civilization (1980). Tresham pioneered another category of games prior to Civilization:the “18xx” genre. In 1974, Tresham released 1829, the first 18xx game. In it, players compete to make the most money operating British railroad companies. Since then, dozens of train games have emulated its design. Funnily enough, Sid Meier took inspiration from Tresham again, launching a single-player video game version of 1829 called Railroad Tycoon (1990). However, the unique player interactions in Tresham’s work were lost in Meier’s single-player adaptation.
While there are over 150 18xx games, all cleave close to the original. When players discover a new title in the genre, they often skip the rulebook and read a few paragraphs which contain the rule changes from the original.
In this blog post, I set out to explain the 18xx genre’s unique ideas, not just because they are brilliant game design patterns, but because they are particularly suited to on-chain games.
So what is so special about 18xx games?
The 18xx genre adds a meta-layer to the traditional board game. In these games, companies lay tracks and buy trains. Each company comprises shares that players can own. The player with the most shares in a particular company at a given moment operates that company. There are several details that go into making this structure work, and I encourage anyone interested to start by reading the rules to 1846: The Race for the Midwest. For the purposes of this blog post, you need only understand that players use their funds to invest in various train companies in the hope of growing them as businesses.
For example, let’s say Alice owns 20% of the shares of Swansea and Mumbles Railway and 40% of Great Northern Railway (GNR). Bob owns 20% of GNR and 30% of Great Central Railway. Since Alice has the most shares of GNR, she decides which trains GNR buys, what tracks it lays and what dividends it pays.
If GNR holds 40% of its own stock and Alice decides to pay out £100 of dividends, then she receives £40, Bob gets £20 and GNR keeps £40 to go towards laying more track next turn. Bob is receiving passive income. He did not “do” anything other than purchase shares in a company Alice is controlling.
Importantly, if Alice needs GNR to gain operating capital, she needs to buy more shares from GNR itself. This is the twist that confuses new players. Just because you have money does not mean the companies you operate have money. Finding ways to get cash in and out of the various train companies is the name of the game.
Excitingly, the 18xx enjoys emergent behaviours such as hostile takeovers, rug pulls, and cartels. At the end of the game, it’s the richest player, not train company, that wins.
What is the Pitch?
We should replace on-chain game players with fictional corporations. This design pattern will add a proven and interesting layer of game mechanics. While I do not think this pattern could overlay every game, it would be particularly suited to those where players would normally compete over generating resources.
In Part One of this series, I wrote about the throughput limitations of on-chain games. I have since been looking for games that port best to a blockchain, based on the number of chained actions per second. My research has brought me to Tresham’s work. Here is why it works on a blockchain:
- Thoughtful turns. Players need to ingest the complexity of the board, the intentions of their opponents, the valuations of the various companies and then make select strategic decisions. Players should be comfortable moving only once every few minutes.
- Social interaction. Negotiations are an important part of 18xx, and since these are non-binding, they do not need to be recorded to the game-state. That entire layer of play can remain off-chain.
- Composite turns. When operating a train company, players execute a series of moves at once. This means the game state is updated fewer times, reducing the tps. But better than that, since a train company always makes the most profitable move, an entire round, including each company’s moves, can be completed in one tidy transaction.
- Getting Tech for Free. Since the 18xx genre is inspired by the physics of finance, it can leverage existing DeFi and DAO protocols. Prebuilt on-chain auctions, markets, and fractional ownership are ready to be composed with new game development. This is particularly exciting to me because it leverages an affordance as opposed to avoiding a limitation.
Someone needs to build this. It will be complicated to optimize, there will be rule-set tradeoffs, and there needs to be a focus on modularity. If you are that someone, hit me up in my DMs @DangerWillRobin, I’d like to help.
Special thanks to my reviewers
@0xHank
