
- BGG rank
- BGG #5,404
- BGG rating
- 6.9
Imperium: Empires in Conflict – Worlds in the Balance
- 2 players
- 180–300 min
- Complexity 2.6/5
- 1977

1973
Rules assistance for Triplanetary
Plain-language explanations of turns, card effects and disputed situations, with official source references and saved question history.
For 2 players

What would you like to know?
Answers come from the official rulebook, with the page to check.
Triplanetary is a board game released in 1973 for 2–3 players, 45 minutes per game, and ages 12 and up. It was designed by John Harshman and Marc W. Miller and its main mechanics are Dice Rolling, Grid Movement, and Hexagon Grid.
Set in the 21st century, the map depicts the inner Solar system out to Jupiter. Scenarios involve racing, pirating, invasions, and a few others. Movement involves vector mechanics. Players plot courses using a grease pencil on the map and use fuel to accelerate a maximum of one each turn. Planets and moons are used to modify the trajectory. There are a limited number of ships. Most are limited in fuel, so making efficient use of gravity is important to reaching a destination. 2nd edition came out in 1981. A 3rd edition was released in 2018 by Steve Jackson Games. It is fairly easy to extend the game to much more than 3 players, although the board can become cluttered with ship trails (the game is sorta like Crayon Rails in this respect).
Triplanetary supports 2–3 players according to the catalogue. This range comes from the publisher’s listed player count, so the game can be set up for any group size within it. Some setups, rules and scoring details may still vary by player count, so check your edition’s rulebook for the exact configuration.
The listed playing time for Triplanetary is 45 minutes. This is the publisher’s estimate for a full game. The actual duration depends on the group, the player count and familiarity with the rules: first sessions usually run longer, while experienced groups often finish faster. Setup and teaching time are not included in this estimate.
The catalogue lists Triplanetary for ages 12 and up. This is the publisher’s recommendation and reflects reading demands, rule complexity and small components rather than theme alone. Younger players can often join with help from an adult, so check the age guidance on your edition and consider your group’s experience with board games.
Triplanetary has a complexity rating of 2.3 out of 5 from BoardGameGeek players, which makes it a medium-light game. The rating reflects how much rules knowledge, planning and decision-making a typical game demands. Expect a longer first teach for heavier games, and use a preparation guide before game night.
Triplanetary belongs to these categories: Wargame and Science Fiction. Its main mechanics are Dice Rolling, Grid Movement, and Hexagon Grid. Categories describe the theme and setting of a game, while mechanics describe what players actually do on their turns. Each mechanic links to a catalogue hub with similar games, which helps when you want something comparable.
The credited designers of Triplanetary are: John Harshman and Marc W. Miller. These credits come from the published game data and name the people responsible for the game’s design, not its illustrators or publishers. Designer pages on MeepleRules collect other titles by the same designers, which helps when you enjoy a game and want to find similar ones.
The catalogue lists Triplanetary as a base game. It can be played on its own with the components in the box and does not require any other title. Expansions, if any exist, add new content or rules on top of it and are listed separately in the catalogue with a link back to this base game.