Hadron
Hadron Rulebook
Table of Contents
Table of Contents
Placement Rule
You can place a tile in isolation, not adjacent to anything. Or you can place a tile to form one (horizontal or vertical) adjacency with a friendly tile and one adjacency with an enemy tile. Or you can form two adjacencies with friendly tiles and two adjacencies with enemy tiles. See Figures 1 and 2, which show all legal placements.
Figure 1 — legal placements on a 3x3 fragment
Each of the five diagrams below shows a 3x3 fragment of the board with green checkmarks over every empty square where a placement is currently legal.
- Fig. 1a — The fragment is completely empty. Every square is checked: with no tiles on the board yet, every placement is an isolated placement, and isolated placements are always legal.
- Fig. 1b — A blue tile sits at top-middle and a red tile at middle-left. Checked squares: top-left, middle-middle, middle-right, bottom-middle, bottom-right. Unchecked: top-right and bottom-left, because each touches only one existing tile (an unmatched single adjacency, neither an isolated placement nor a matched 1-friendly/1-enemy pair).
- Fig. 1c — A red tile sits at middle-left and a blue tile at middle-right. Only the three middle-column squares (top-middle, middle-middle, bottom-middle) are checked. Top-middle and bottom-middle are isolated placements (not touching either colored tile) and so are legal; middle-middle touches both the red and the blue tile, one adjacency each, so it is also legal. The four corners are unchecked because each would touch exactly one of the two colored tiles — an unmatched single adjacency.
- Fig. 1d — Red tiles sit at top-middle and middle-left; blue tiles sit at middle-right and bottom-middle. Checked squares: top-right (touches the top-middle red and the middle-right blue — one adjacency each), middle-middle (touches all four placed tiles — two red, two blue), and bottom-left (touches the middle-left red and the bottom-middle blue — one adjacency each). Top-left and bottom-right are unchecked: top-left touches only the two red tiles (two friendly, no enemy), and bottom-right touches only the two blue tiles (two enemy, no friendly) — neither is a legal pattern.
- Fig. 1e — Blue tiles sit at top-middle and bottom-middle; red tiles sit at middle-left and middle-right. All four corners and the center square are checked. Each corner touches one blue tile and one red tile (one adjacency each), and the center touches all four placed tiles (two blue, two red) — both are legal patterns.
Figure 2 — legal placements on a 5x5 board
A 5x5 board partway through a game, with red and blue tiles scattered across it. Reading the board row by row, top to bottom, the legal (checked) squares are: row 1, column 1; row 1, column 4; row 1, column 5; and row 2, column 2. Every other empty square on this board is unchecked, because a placement there would create an unmatched adjacency count rather than an isolated placement or a matched 1-1 or 2-2 friendly/enemy pair.
Object of the Game
The last player to make a placement wins. If you don't have a placement available on your turn, you lose. See Figure 3, in which there are no legal placements.
Figure 3 — a finished game
A full 5x5 board packed with red and blue tiles and no empty squares left checked: no matter which empty square the player to move considers, it either already borders friendly and enemy tiles in an unmatched count, or the board offers no way to complete a legal isolated, 1-1, or 2-2 placement. Blue made the last placement, so with no legal placement available Red loses and Blue wins.
Author's Note
Feel free to publish this rule sheet and to program the game of Hadron. No licensing fee or royalties are expected. However, please don't change the name or the rules, and please attribute the game to me, Mark Steere. My other games can be found at marksteeregames.com.
Copyright (c) August, 2022