Updated: Apr 2, 2022
Although the base game of Catan is designed for 3-4 players, my fellows and I have long agreed to only play Catan with three players when we are doing it competitively. We would rather one of us be the banker or audience than make the game four-way. The way we see it, there are currently five reasons to play Catan as a three-player game.
The hexagon board is the most obvious reason that we can think of, as 6 can perfectly be divided by 3, not 4. It could have been the other way around if the board had had the shape of a square or an octagon. Additionally, many other things in Catan revolve around the number 3, such as 9 total ports or 18 productive terrain hexes.
Since the board size is unchanged regardless of three or four people playing, games with three feel more enjoyable when the board is more spacious and accessible to all parties involved. Furthermore, the difference in advantages/disadvantages between the first and last settlement-picker will be less devastating for either's chance at winning. Surprisingly, the game may become more competitive due to everyone's more equal standing, which encourages participants to strive for victory with their own efforts rather than blaming bad luck or any unfavourable circumstances.
Even though emptying your hand is a good way to maximise your resource-usage efficiency, stocking your hand is also an equally valid tactic. Despite carrying a certain risk, hand stocking not only opens up more options to utilize your resources but may also allow better optimization for your expenditure. For example, say you have 01 Sheep, 02 Wheat, and 02 Ore, if you wait until your next round, you may gain an extra Sheep, which can be used to draw 02 dev. cards, or an Ore, which helps upgrade a city. Were you to spend on a dev. card beforehand, you would have missed the opportunity for an upgrade. High-level players stock cards in hand regularly because they see stocking as an option with its own pros and cons to be analysed, rather than a must-avoid status. However, such a useful tactic becomes less effective, even rendered invalid due to an increment in stake when you have to wait for 04 dice rolls instead of 03 before you can spend your resources. The biggest hindrance of this tactic is the number 7, which will occur more frequently with more dice rolls per round.
Going a bit deeper into in-game strategies, four-player Catan rewards an already annoying and overpowering strategy - spamming development cards, while indirectly punishing the official road-building style. Indeed, when you play with four players, it is not a hard task to put your robber on a hex with multiple players; meanwhile, it can be impossible in a lot of three-player games. Also, Monopoly is the absolute superior dev. cards when you have three enemies to confiscate. Back to the players that love building roads, it is apparent that they have less freedom on a board with 08 starting settlements than the one with 06.
And last but not least, a game with three players is less demanding in effort and time to be made, no matter whether you are gathering people to play on a physical board or queuing for an online game. When you have to wait for only 02 dice rolls until your next turn instead of 03, it automatically translates to less idling time and faster games. Being able to finish games more quickly without compromising their quality is one of three-player Catan's beauties.
Thank you for reading! As always, you are welcome to give feedback and share your thoughts. Good luck, have fun!