The 4th Expansion is a set of 4 game boards with Monasteries printed next to the play area.
The following rules are then added to the basic game play of "The Castles of Burgundy":
- As soon as a player creates a direct, straight connection between two monasteries with 5 connecting tiles on his game board, he earns 5 victory points.
- The first player to complete all three connections between his monasteries wins an additional bonus of 5-7 victory points (for a 2-4 player game). The second player to complete all three connections wins 2-4 victory points.
This means that a player can win a maximum of 3x5 + 7 = 22 additional victory points over the course of one game.
For more information, visit the BGG listing.