Choose your next move by selecting a non-tree cell that can still preserve four constraints: four tents for four trees, exact row and column clues, one-to-one orthogonal tree pairing, and no tent contact in any of eight directions.
That process matters on the fixed 5×5 Tents Puzzle board, where every tentative placement is checked against the complete rule set. Four trees are fixed and exactly four tents must be added. The goal is not merely to put four tents near trees; all counts, pairings, and spacing must agree at the same time. A tent pairs with a tree only when the cells share a top, bottom, left, or right edge, and diagonal contact does not create a tree-and-tent pair.
Read the clues before looking for cells
Each number around the board is an exact target, not a minimum. The board displays the current tent count beside every row and column clue, so begin by finding the lines that are already full. If a row currently contains its required number of tents, another tent cannot go in that row. The same applies to a column. A line with a clue of zero is closed from the start.
Next, look for an unmet row and an unmet column. A non-tree cell at their intersection is a possible candidate, because any eventual tent placed there would contribute to both counts. That intersection is only a starting point: the cell must also have a suitable tree relationship, enough space around it, and a place in the one-to-one matching.
The underlying rules are the standard Tents rules documented by Simon Tatham’s Portable Puzzle Collection and GridPuzzle’s Tents rules guide.
Test every candidate against the same checks
Use the following filter before committing to another tent. It separates basic location checks from the harder global matching requirement.
| Check | A candidate passes when | If it fails |
|---|---|---|
| Cell type | The cell is not one of the four fixed trees. | Move to an available cell; tree cells cannot be changed. |
| Row capacity | The row’s current tent count is still below its clue. | Remove any tent that pushed the row above its target. |
| Column capacity | The column’s current tent count is still below its clue. | Remove any tent that pushed the column above its target. |
| Tent spacing | None of the cell’s eight surrounding cells contains a tent. | Remove the touching tent or choose another candidate. |
| Tree access | The cell is directly above, below, left, or right of at least one tree. | Do not place a tent there, because diagonal trees do not count. |
| Inventory and matching | The board can still assign every placed tent to a distinct tree, with no more than four tents in total. | Reconsider the tentative placement before adding another tent. |
The matching check is the one most easily misjudged. A tent may stand beside more than one tree, so counting nearby trees does not prove that the assignment will work. This implementation uses a bipartite matching check to verify that the placed tents can be assigned to distinct trees. Use the current tent count and number of matchable tents above the board, along with any contradiction warning, to confirm that a tentative placement remains viable.
The spacing check is stricter than the pairing rule: a diagonal tree does not form a pair, and a diagonal tent is still forbidden as contact. The dedicated explanation of Can Tents Touch Diagonally in Tents Puzzle? No clarifies that distinction.
Choose and place your next tent
- Read all five row clues and five column clues. Note which lines already meet their exact totals and which still need a tent.
- Exclude full lines. Do not consider placing another tent in a row or column whose current count already equals its clue.
- Move the cursor with the arrow keys. Focus on an empty, non-tree cell at the intersection of an unmet row and an unmet column.
- Check orthogonal tree access. Confirm that the cell shares an edge with at least one tree. A diagonal tree is not sufficient.
- Check all eight neighbors. The cell must not touch another tent horizontally, vertically, or diagonally.
- Press Space to place one tentative tent. The browser recalculates the full rule set after every tent change.
- Review the feedback. Compare the current row and column counts with their clues, check the matchable-tent count, and look for contradictions. If the placement fails, press Space again to remove it.
- Repeat until four tents are valid. Continue testing one cell at a time rather than stacking several uncertain placements and trying to repair them later.
Use the controls to test ideas safely
The controls distinguish a tentative tent from a permanent grass note. This makes it possible to test a promising cell, inspect the consequences, and reverse the placement without restarting the whole puzzle.
| Control | Result | Practical use |
|---|---|---|
| Arrow keys | Move the cursor between available cells. | Scan row and column intersections. |
| Space | Place or remove a tent on an available cell. | Test a candidate and undo a conflict. |
| Enter | Add or remove a grass note on an empty non-tree cell. | Record a square you believe cannot contain a tent. |
| Mouse or touch | Click an available cell to toggle a tent. | Use a pointer alternative to keyboard play. |
| Restart | Clear the board and its scoring state. | Begin a fresh attempt after a major change of approach. |
Tree cells are immutable. An attempted tent or grass action on a tree does not change the board and does not consume a move, so there is no scoring penalty for selecting an unavailable cell.
Undo a contradiction instead of restarting
The validation system checks the whole board after each tent change. It detects several specific failures:
- Horizontal, vertical, or diagonal contact between tents.
- A row or column containing more tents than its clue allows.
- A tent with no possible neighboring tree.
- Multiple tents competing for too few distinct trees.
- More tents than the four-tree inventory can support.
- A tent placed on a tree.
A validation warning does not block the placement or turn the attempt into an irreversible loss. The contradiction remains editable: use Space to remove the conflicting tent, then continue from the corrected position. Restarting is useful when the whole approach has stalled, but it is not the normal response to one incorrect cell.
Distinct-tree matching explains why an apparently sensible move can still fail. A tent beside two trees is not automatically wrong, and two tents that each touch some tree can still compete if they cannot be assigned to different trees. Remove one and reassess the remaining candidates rather than adding another tent to “fix” the count.
Mark certainty with grass notes
Press Enter on an empty non-tree cell to add or remove a grass note, which records your belief that the square cannot contain a tent. Good candidates for a note include a cell in a row or column that is already full, a cell touching an existing tent in any of the eight surrounding directions, and a cell with no orthogonally adjacent tree.
Grass is only a reasoning aid. It does not affect validation, count toward a row or column clue, or establish a tree pairing. Use Space rather than grass when you want to test an actual tent placement. Because every grass action subtracts 10 points, reserve notes for exclusions that make your next deduction clearer.
Finish with four valid tents
A completed board must satisfy four conditions simultaneously: there are as many tents as trees, every tent can be matched one-to-one with an orthogonally adjacent tree, no two tents touch in any of the eight surrounding directions, and every row and column contains exactly its clue total. Once the fourth valid placement completes the board, play freezes until you select Restart.
The score is calculated as max(0, 1,000 − 10 × actions), where each tent or grass action counts. A clean solve with four tent placements and no notes follows 1,000 − (4 × 10) = 960 points. Extra placements, removals, or grass notes each lower that result by another 10 points.
Restart clears the tents, grass notes, move count, score, and contradictions. A completed best may be stored only in the browser’s local storage. The most efficient next step is therefore always the same: narrow with the clues, test adjacency and spacing, place one tent, and use the live matching feedback before committing to another placement.
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