The Best Monopoly Strategy, Tested on 300M Games [video] | Hacker News Reader

The Best Monopoly Strategy, Tested on 300M Games [video]

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Forty six years ago this was the second thing I ever programmed on a computer. It was a TRS-80 model 3, and initially Quick BASIC was the only software I had for it. My first project was a todo app. The second was a Monopoly simulation that just ran around the board to estimate which squares were landed on most often. It worked, and the high I got from that addicted me and kicked off a coding career. That damn computer should have come with a warning label.

> The second was a Monopoly simulation that just ran around the board to estimate which squares were landed on most often.

This was one my most significant works in HS. I think I used a BASIC compiler for my Apple IIc so it could run faster. I felt powerful solving problems that could only be solved via Monte Carlo methods* and took a long time to compute.

* I am aware you can compute long run landing probs via matrix calcs. However, this matrix gets yuge when you factor in some sort of probability distribution for how long a player decides to stay in jail for (either roll out or pay your way out). This is someone similar in shape, but not scope, when Eli talks about Combinatorial simulation - the game of SET.

https://eli.thegreenplace.net/2026/monte-carlo-simulations/

That's awesome, I know that initial feeling of being able to create and seeming like the sky is the limit.

I used to watch the workers at Radio Shack play Attack Force on the Model III and once I could afford a CoCo I learned how to make games by making that one.

They don't say what the strategy is in the comments (duh) but I seem to remember a similar study from years ago saying the optimal strategy was to always buy if you can.

Meta, but one rule I was surprised to learn: if someone doesn't buy a property when they land on it, it is immediately auctioned off by the bank.

Another interesting strategy was to not upgrade to hotels in order to create a housing crisis by using up all the houses

i recall always playing with a house rule where you can pay some large amount to immediately build hotels, but cant recall if this made the game more or less "problematic".

Many people play without the auction rule (hence, they don't even know it exists).

> I seem to remember a similar study from years ago saying the optimal strategy was to always buy if you can.

The optimal rule is a little different: don't sit on cash until a housing crisis.

Just like in a real-life business, sitting on cash that could be working for you is a bad idea.

Monopoly Junior works like this already - you MUST buy a property you land on, if you can't buy it for any reason the game ends.

It really works when playing with kids, but I noticed that the consequence of it in most games is that the player who goes first usually wins.

> the player who goes first usually wins

That is the point the game is meant to teach. Literally.

The original game developed by Lizzie Magie is a didactical game to illustrate the problems of monopolies accumulating ever more wealth.

It is crazy that we seemingly forgot the message and keep playing this game. Even on a purely “is this fun” level there are so much better games.

I got that message loud and clear when playing this the first time.

I thought the best Monopoly strategy was not to play.

How about a nice game of chess?

WarGames (1983)

Before posting, I always do a ctrl+F, and I was glad to see my search for "not to play" found a hit.

I find a game of Monopoly so boring and it takes too long to play.

And also I was thinking of WarGames.

You can do the official short game rules, but that is still slow. We go further, when we play we randomly deal out all the properties then buy trade amongst ourselves. This way we start with all the properties owned and you can start building houses immediately. Ymmv

Also more realistic for the modern property market to start off having inherited a bunch of properties instead of buying them yourself.

I enjoy a monopoly variant where every property landed on causes an auction regardless of who landed on it.

Oh, I like this a lot!

We recently picked up Monopoly with a new generation of players, and the flaws of the design were now apparent to adults. I think this could be a significant improvement.

Uh, isn't that the official rules? If a player lands on an unowned property, it goes to auction[0] EDIT: if the player doesn't buy it for the price printed on the board.

[0] https://officialgamerules.org/game-rules/monopoly/

No. Only if the player declines to buy it.

Corrected. Thanks. So the OP is playing with a variant where the original player landing on it doesn't get the first bite at the apple at the printed price?

Yes that's right

That almost makes me want to play a game of Monopoly.

It's surprising that a content creator would put this much work into a video and then use an AI narration.

well how much work did he really put into it?

It feels like making "Where the tokens land was checked against the table published in Scientific American in 1996 (Illinois Avenue: 3.18% published, 3.19% in my simulation)." a key point of the investigation doesn't see like a human choice

Did you switch on YT auto translation by accident?

Yeah it's a bit weird that it gets a different accent for part of the video.

But some people are not great speakers - I can imagine using AI narration if you don't feel like your own speech will meet your own standards.

A couple Thanksgivings ago, I played with a couple of alpha finance types that I'm related to at a distance of several marriages. It's certainly a more interesting game the way they play it, no doubt helped by everyone being amply lubricated and some enthusiastic brotherly backstabbing. Whether it's more fun or not probably depends on exactly how much you care about the outcome. It still took the better part of a couple hours though.

That sounds like my family, we do crazy setups and deals which make the game take hours and has made many people refuse to play monopoly with us. The most creative strategy my brother came up with is roll insurance, where if you are about to roll with a chance of landing on a bankrupting property, he would calculate the probably and let you pay him a flat fee to cover your roll.

Sad that that a "buy everything" strategy performs best. It's not a strategy which varies much based on other players behaviour which makes it hard to counter and therefore boring as everyone has to play that way. I guess where there's still room for adaptation is the auctions if the player landing on the space can't afford to buy. The bidding strategy here forces some player interaction and room for different strategies...

AlphaZero (Google's chess bot) famously started with no 'book knowledge' (e.g. ideas on how to play chess), instead, it learned by playing against itself many, many times over.

Has anyone done something similar to that with Monopoly? (by contrast, the technique used in this video is much more basic; it comes up with some specific rules a player will use, then has those bots play eachother)

I have thought it couple of times, most recently after this video. I so want to make it since I feel all these videos tend to lack two things the zero-style would offer.

One: it would offer no human assumptions.

Two: more importantly it should and could include the trading part. (the op's video had some, but it felt really really limited from what I gathered)

It is really rare to see trading to be implemented. Yeah, it is the hard part but in competetive monopoly, it is big part.

I am yet to figure both input/output spaces for it. As soon as I figure them, I probably will do proper zero-style ai for many games.

Isn't trading always blocked? Whenever you would allow someone to build a complete Color it's better not to allow it, and whenever you also would it's only advantageous if your color is stronger than the other thus the other party should never agree.

Any other exchange becomes pointless as you won't be completing a color anyways.

You seem to reason in terms of trying at all costs to block the other players, not to maximize your gain. I agree the ultimate goal is to do better than all the others, but the tactics to get there may involve temporarily favoring other players in win-win exchanges to grow quicker, or to block a third player already far ahead, etc.

In the second case, the stronger color can be offset by giving the weaker color more cash / other properties.

There is also the case when you don't kind a want to buy the property and it goes to action. Now you can bid again, hoping for cheaper prices or to take risk and try to drive to price as high as possible for the actual buyer. Same possibility exists for any auction.

This was tested in the video. Players that don't trade lose. Refusing trades where the opponent gets a better set underperforms always trading to complete your sets.

As I have let this simmer in my mind, one really great way to drop the interactions needed to complete auction, could be ducth action. I think it is called that. (the auction where everone submits their maximum that they are willing to bet in secret. Winner of the action is highest bet, and they pay the second highest bet as winning bet.)

This could reduce the input space and define it such that it allows this thing. Hmm.

It'd be interesting if the strategy would change without the auction rule. I don't think I've ever played with that.

I think the strategy is to buy houses and never hotels. Hotels free up the housing supply. If you buy all the housing supply and never use hotels, you've cut off the only method of earning a lot more money for other players.

Never build until the pay per house and hotel chance is drawn. It's the level 2 signal.

So the conclusion is « buy everything even with borrowed money, but anyway it’s mostly a game of luck and even with the best strategy you’ll loose most of the time».

Not a bad model it seems, curious to test against a « I never want to die strategy », where everyone saves enough to keep playing, which is what mostly happens in real life too.

In the end, it aligns with YC and the startup model to try the all in for a project that will make you win disproportionately.

Of course you will lose a game of chance most of the time. Over a long enough timeline the chance of winning probably comes out to evenly distributed. Therefore your best bet is to play with only one other person ever so that you have a 50% win rate

my takeaway was "invest everything in everything you can" instead of "all in in one project"

The video does test against a "saver" player that keeps a buffer. They perform badly.

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