The Liberty game was created at the end of WWI and what follows is based on examining the only part available, the game board.

Apparently the player moves along the path via a die roll, fighting against the color coded units the player lands on (possibly facing at least 3 levels of combat, each new challenge coming after winning a previous battle). Each victory earns points.

The assumption is that after all players have returned to the USA the player with the most points wins.