Step 3 of 6
Tents need elbow room
Pitch one tent and its whole ring is decided: every neighbor, grass.
The rule of thumb: No two tents touch, even diagonally. Pitching a tent turns all eight neighbors to grass.
No two tents may touch — not side by side, not corner to corner. So the moment a tent goes up, every cell around it turns to grass. That ring is the most information a single move can give you, and it feeds everything else: lines shrink, trees lose options, counts get closer to closing.
Run it in reverse while you’re weighing a clearing: if a tent there would touch one already pitched, the clearing is grass. These practice boards are picked so the rings are load-bearing — leave them unmarked and the board stalls before the win.
Where to look: Every tent you place, before anything else: its eight neighbors. Fewer on the edges — five along a side, three in a corner.
Worked example
A real position from a board that needs Tents need elbow room. Purple: what the reasoning rests on. Dashed: the cells in question. Green: what it proves.
Rings marked. Next: the trees themselves, and the tents they force. Step 4: One tree, one tent →