Overview

Cathedral is a two-player abstract strategy game where players place building-shaped pieces on a 10x10 grid board. The goal is to position all of your buildings within the walled perimeter while blocking your opponent from doing the same. Players score by having the fewest unplaced building squares at the end of the game. The game features territory claiming through wall-to-wall connections.

Components

• 1 game board (10x10 grid with perimeter walls)
• 1 Cathedral piece (neutral)
• 14 Light-colored building pieces
• 14 Dark-colored building pieces

Each set of 14 buildings consists of pieces of varying sizes (occupying 1 to 5 squares each).

Setup

1. Decide who plays Light and who plays Dark.
2. Distribute the 28 buildings accordingly, placing them in front of each player.
3. The Light player places the Cathedral anywhere on the board, aligned with the grid.
4. The Dark player makes the first building placement, then players alternate turns.

Turn Structure

On each turn, a player places one of their unplayed building pieces on any vacant space on the board, keeping it aligned with the grid squares. Once placed, a building cannot be moved.

Actions

Place a Building: Choose one of your unplayed buildings and place it on the board. The piece must fit entirely within the grid and cannot overlap other pieces.

Claim Territory: Create enclosed areas (wall-to-wall connections) using your own buildings and the board perimeter. Claimed territory rules:

• If you enclose exactly ONE opponent’s piece (or the Cathedral alone), you MUST remove it immediately. The opponent may replay the removed building later. The Cathedral, once removed, is not replayed.
• If you enclose TWO or more pieces (including possibly the Cathedral), NO pieces are removed and the space remains available to your opponent.
• Only your own buildings (not the Cathedral) may form your wall-to-wall connections.
• Corner-to-corner contacts do NOT count as valid connections for claiming territory.

Scoring / Victory Conditions

The game ends when neither player can make a legal move. Players count the number of squares occupied by their unplaced buildings. The player with the lowest total wins.

For a full match, play two games: one with each player placing the Cathedral first. The player with the lowest combined score wins.

Special Rules & Edge Cases

• Neither player may claim territory on their first building placement move.
• The Cathedral is neutral and cannot be used as part of your wall-to-wall connection to claim space.
• Claimed territory (enclosed by your buildings) is unavailable to your opponent; only you may place buildings there.
• Try to position larger buildings first to maximize territory claims.
• Do not place buildings in your own claimed territory while unclaimed space remains available.

Player Reference

Turn sequence:

1. Place one building piece on any vacant grid-aligned space
2. Check for enclosed areas with exactly one opponent piece (must remove it)
3. Turn passes to opponent

Territory claiming checklist:

• Enclosed by YOUR buildings + board walls only
• No corner-to-corner contacts (must be edge-to-edge)
• Exactly 1 enclosed enemy piece = remove it
• 2+ enclosed enemy pieces = no removal
• Cathedral counts as a piece for removal purposes but cannot form your walls