Tritium is an abstract strategy game for two players, who take turns creating and growing regions, and claiming them. Once the board is full, the player who controls most tiles wins.

• Board: a hexagon of hexagons without its center cell. Recommended sizes are 5 to 7.
• Hexagonal tiles in three colors, each in an amount equal to the number of cells of the board divided by three. These pieces are shared by both players.
• Player flags in two colors, in sufficient quantities.

Prepare one flag for each player next to the board, keep the rest in a supply.

A region is a complete group of connected cells containing tiles of a single color. A region is free if it contains no player flags. A player controls a region if they have a strict majority of flags in it.

Players take turns. On their turn, a player must take one of the two possible actions:

1. Place a hexagonal tile of any remaining color on any empty cell. OR
2. If they have a flag of their own color prepared next to the board, place it on top of any tile in a free region. Once both prepared flags have been played, prepare again one flag for each player.

If they cannot perform any of these two actions, they must pass.

The game ends when both players pass in succession, that is: all the tiles have been placed, and there are no more free regions.

• Each player's score is the total number of tiles in all the regions they control.
• The player with the highest score wins.
• In the rare case of a draw, the player who played a flag first loses.

Using prepared flags next to the board is simply a visual way to represent the equivalent rule: one can play a flag only if they have fewer than or as many flags as their opponent on the board.

For a quicker and more tactical game, play on a small board (size 4 or 5), with the following alterations:

• During setup, prepare three flags for each player next to the board. There is no restriction on when to play these flags.
• Do not replenish these prepared flags when they run out.

Version 1.0 of the rules.

Copyright © 2024 Noé Falzon, under CC BY-NC 4.0 license. I would love to hear if you enjoy the game, implement it or modify it!

Original rules document

Grow three colours of hexagonal tiles and claim regions with flags. Most claimed tiles after both players pass wins.

Inventors: Noé Falzon (Castux)

Published listing: BoardGameGeek: Tritium.

The game ends on consecutive passes. Score the number of tiles in regions you have flagged. Higher score wins. If scores tie, the player who planted the first flag of the game wins.

Empty hexhex, default size 5. A shared supply of three tile colours. Each player has flags (unlimited in long form; three each in short form).

On your turn, either:

• Place a remaining tile colour on an empty cell, or
• Plant a flag on an unflagged tile you can claim: the connected region of that colour becomes yours.

If you have no placement or flag, you pass.

Play until all regions are claimed (default).

Only three flags each.

• Current engine version: 1.0. On Abstract Play since 2024-08-26.

• https://boardgamegeek.com/boardgame/430859/tritium