Zero lines: eliminate without placing a tent
A zero clue gives certainty immediately. It can also remove candidates for trees in neighbouring lines, making a later count or adjacency deduction possible.
LEARNING CENTRE
Tents & Trees: make every constraint agree
Place tents by combining counts, tree neighbours and separation. A square may satisfy one rule and fail another. These exercises teach you to eliminate impossible locations before committing to a tent, then check the complete one-to-one tree matching.
Rules you need at the board
Put one tent beside each tree, directly above, below, left or right. Each tent belongs to one different tree. Tents cannot touch, even diagonally. The row and column counts give the required number of tents. Mark grass where a tent cannot go.
Four techniques to practise
Tree neighbours: necessary does not mean sufficient
List the squares a tree could actually use, and distinguish them from squares that only look nearby. Keep the eventual one-to-one matching in mind when trees share candidates.
Tent spacing: check the corners too
Placing one tent often rules out several nearby squares. Those exclusions can be more useful than the placed tent itself when you return to the row and column totals.
Remaining counts: finish a line in either direction
A nearly completed row can tell you either where tents must go or where they cannot go. Count the remaining requirement and the remaining legal locations separately.
Follow a practice collection
1. Clear impossible tent squares
Start with zero lines and the four-direction tree rule. Learn why a promising-looking square can be grass before any tent has been placed.
2. Let one tent change the board
Use tent exclusion zones and remaining row or column totals together. Check how an elimination changes the next line rather than placing tents from appearance.
3. Finish the counts, then check the pairing
Combine eliminations and placements, and finish by assigning each tent to a different tree. Shared tree neighbours are included so that matching cannot be replaced by a quick visual count.
What the explanations can establish
An adjacent tree is necessary for a tent but does not prove the square must contain one. A tent beside two trees cannot serve both. Completed counts and non-touching tents still require a valid one-to-one matching. The introductory exercises do not teach every matching deduction needed by harder boards.
Hints in this study area use the current marks. In Nonograms, Tents and Bridges, deductions assume earlier marks are correct; a local conflict stops the suggested step, but absence of a warning does not certify every mark. Minefield flags are never used as evidence. Cross Lights tests complete first-row choices and verifies the resulting plan.
Read a complete illustrated solve
Follow the original board walkthrough, with before-and-after diagrams and a final rule check. It is available without JavaScript.
Keyboard: Tab to controls and press Enter or Space. Board state saves locally; no account is needed.
DECISION LAB
Every tree has a neighbour. Two trees still cannot share it.
Audit a completed-looking camp using distinct tree–tent partners, then repair it without changing any clue.
Test your prediction and follow the evidence →