Colouring Techniques for Tents and Trees

Tents and Trees presents a grid of trees, empty land and tents. Every tree needs one orthogonally adjacent tent, every tent is paired with one tree, and no two tents may touch, even at a corner. Visual bookkeeping becomes important when several possible placements compete for the same cells.

Colouring techniques turn possibilities into a readable map rather than a collection of guesses. By separating candidates, confirmed placements and blocked squares, you can see which deductions still matter. The method works with a pencil at a kitchen table, a printed grid at a community hall or a timed tournament sheet.

Why visual marking changes the solve

Visual marking changes a solve because colour exposes relationships that are hard to hold in memory. A blue candidate is an empty square adjacent to an unpaired tree, not yet a tent. A red square has been ruled out, while a black tent is confirmed. Keeping these states separate prevents a plausible placement from hardening into an assumption.

The useful question is not which colour looks likely, but what information each shade removes. Colour groups cells sharing a constraint, identifies a contested square and shows the reach of a placed tent. Use two colours plus hatching if shades are hard to distinguish; the reasoning matters more than the palette.

Build a colour key you can trust

Start with a key that survives pencil smudging and crowded notation. For example, use blue outlines for live candidates, red hatching for excluded cells and a dark filled symbol for confirmed tents. Give each tree a letter so you can trace a candidate back to its source. Add a dot or underline as well as colour, especially for colour-blind solvers or greyscale printouts.

Temporarily outline each tree’s candidate set. A cell carrying only tree A’s mark belongs to A; a cell carrying both A and B is contested. If A has one candidate, that square is forced, but the letter still matters because B’s claim on it must be removed. This layered notation separates a square’s status from the tree that wants it.

A page refresh can be compared with a bonus balance reload: the display changes while a separate record preserves what has already been established. In puzzle notes, that record is the colour key, so reopening a grid should never force you to rebuild every deduction.

Trace forced pairs without overcommitting

Begin with trees that have the fewest possible tent squares. Place the tent when a tree has one candidate, connect the pair with a light line and mark the tree as paired. Its other candidate squares are now unavailable to that tree. Do not erase the whole board; crossed or faded marks are evidence of why a later deduction works.

Overlapping candidate sets reveal the next step. If tree A and tree B both claim square X but B has no other candidate, B must take X and A must look elsewhere. Marking that conflict with a distinct pattern makes the consequence visible. Three trees competing for only two squares signal a misread grid or an earlier mistake, because every tree requires a unique paired tent.

After each confirmed tent, treat its full neighbourhood as forbidden for other tents. Mark the four edge neighbours and four diagonal neighbours as blocked, while leaving tree symbols untouched. This exclusion zone often creates a new forced pair farther along the grid, giving you a clean chain of deductions rather than scattered trials.

Use a two-pass colouring routine

Before making placements, prepare the board with a simple audit list:

After each placement, run a shorter update list:

Apply the method to clues and competition sheets

Some Tents and Trees sets add numeric, regional or other extra constraints. Treat each as another exclusion layer: fill cells until a stated count is reached, then mark further cells in that area red. Where several clues apply to one row, column or region, check every condition before colouring a candidate live. The standard tree–tent and no-touch rules still apply.

Formal sheets can also compress information into unfamiliar symbols. Zagonetka’s competition notation notes are worth checking before a timed event so that a marker, number or shaded area is interpreted correctly. A notation error can look like a logical breakthrough, especially when a colour seems to force an elegant answer.

At a local meet-up in Sydney or Melbourne, annotate lightly enough that a neighbouring solver cannot mistake a pencil candidate for a printed clue. Keep the legend in a corner and write the puzzle number and orientation beside it. If the grid is rotated during discussion, every candidate set should still make sense.

Practise with Australian conditions in mind

Reproduction conditions matter. Australian homes, offices and printers commonly use A4 rather than US Letter, so scale or print a test page before saving a tournament sheet. In Brisbane’s humid weather, a felt-tip pen may bleed or smear; in Perth’s dry conditions, fine graphite can become pale against textured paper. A short pencil, good eraser and spare copy are more reliable than heavy pressure.

A casual meet-up near the South Melbourne Market can turn colour choices into teachable examples: compare one grid and explain a disputed shade rather than merely declaring an answer. Similar sessions beside Sydney Harbour provide the same useful routine. This beats isolated solving because another solver may read the same hatch as a confirmed placement.

Review each solve by asking what the colour changed. If a red square followed directly from a tent’s exclusion zone, label that deduction; if a blue candidate vanished after pairing, show why. Zagonetka’s schedules, results and practice material can provide unfamiliar grids, while tournament-style notation checks keep your habits aligned with the wider Croatian and international puzzle community.