Starlink: rules, strategy, and free play
Starlink is GridJoy's name for Hidato-style number-path puzzles. An N×N grid contains the numbers 1 through N², but only some of them are visible as clues. Your job is to fill in the missing numbers so that every consecutive pair (k and k+1) occupies adjacent cells — including diagonals. The completed grid traces one unbroken chain from 1 to N² through every cell.
THE RULES
- Fill every cell with a unique number from 1 to N². On a 6×6 grid you'll place 1 through 36 exactly once. Clue cells are pre-filled and can't be changed.
- Consecutive numbers must occupy adjacent cells. Adjacency is 8-directional — up, down, left, right, and all four diagonals. The cell containing 5 must touch the cell containing 6 along one of those 8 directions.
- Every cell is used exactly once. The completed grid is a single Hamiltonian path covering every cell — no skipped cells, no revisits.
BEGINNER STRATEGY
- Work outwards from the clues. If you know where 7 and 10 are placed, the missing 8 and 9 must lie on a 2-step path between them. Count the diagonal + straight distance from 7 to 10 — if it's exactly 3 cells, the path is forced.
- Use forced corner / edge moves. A corner cell has only 3 neighbours, an edge cell has 5. If the corner contains k, then k-1 and k+1 must come from its 3 neighbours — often eliminating half the candidates outright.
- Watch for tight gaps between distant anchors. If a clue says 12 is here and 18 is six cells away (manhattan distance), the 5 unknown numbers between them have no slack — every step is forced. Solve those segments first and the rest opens up.
- Pencil candidate ranges per cell. For cells far from any clue, the candidate range is wide. As you place numbers, ranges shrink. Pencil-mark a cell with its minimum-and-maximum possible value to spot impossible cells early.
COMMON MISTAKES
- Forgetting diagonal adjacency. Starlink uses 8-directional adjacency — up, down, left, right, AND all four diagonals. Players used to square-grid puzzles (4 directions) miss diagonal connections, leading to incorrect dead-end calls and unsolvable-looking grids.
- Not computing the gap between anchors. Two clue cells showing 12 and 18 need exactly 5 intermediate cells between them. Count the available cells in the neighbourhood and confirm they equal the gap size (end - start - 1). If they don't match, you've identified a constraint violation early.
- Ignoring corner and edge constraints. A corner cell has only 3 neighbours; an edge cell has 5. If a corner contains value k, both k-1 and k+1 must come from its 3 neighbours. This is often the tightest constraint on the board — solve corners and edges first.
- Placing a number without checking that its successor can still reach the next anchor. A placement is only valid if it keeps the path continuous to the next anchor. Before placing k, confirm that k+1 is within 8-directional reach of the cell you're placing k into, AND that k+1's cell can still reach k+2.
HOW TO THINK ABOUT IT
Starlink is a Hamiltonian path puzzle with waypoints. The anchor clues divide the board into segments — each segment is a sub-chain between two consecutive anchors. For each segment, compute the gap (missing numbers) and the candidate cells (reachable cells between the anchors). If gap = candidate-count, the sub-chain is forced. Work from the tightest gaps outward, using 8-directional reachability to prune candidate cells. The corner/edge constraint is your strongest tool: start there, then move inward.
WHY THIS PUZZLE REWARDS YOU
Starlink rewards spatial thinkers and path-planners more than arithmetic puzzlers. The 8-direction adjacency means every cell has up to 8 candidate predecessors and successors, which makes the deduction feel exploratory — you sketch potential chains, eliminate, and shrink the option space. Players who enjoy mazes, Numberlink, or any path-routing logic puzzle usually take to Starlink quickly. Grids range from 5×5 (beginner) to 8×8 (expert).
VARIANTS
- Hidato. The original variant name — identical rules. Place consecutive numbers across a grid using orthogonal and diagonal adjacency so every cell is covered. Starlink is GridJoy's implementation of Hidato.
- Numbrix. The same consecutive-number chain puzzle but with NO diagonal adjacency allowed — only orthogonal (up/down/left/right). More constrained at each step, typically resulting in fewer candidate paths at each junction.
- Knight's Tour. Place consecutive numbers using chess-knight moves only. The indirect jump (2+1 squares) makes the path topology radically different and much harder to visualise — same 'cover every cell in sequence' goal, wildly different adjacency.
YOU MIGHT ALSO LIKE
Mazes (square + circular) →
Number-path puzzles on square / circular grids — same path-routing feel.
Hex Mazes →
Path-puzzle on a 6-neighbour hex grid — denser branching than Starlink.
Shikaku →
Spatial partition puzzle — different geometry, same intuition style.
Starlink vs Number Mazes →
Same sequential path — Starlink adds diagonal moves, four neighbours becomes eight.
Beginner mistakes in logic puzzles →
Path puzzles reward backing up — five mistakes that block that habit.
Starlink / Hidato strategy for beginners →
Sort gaps by size, fill smallest first — they cascade and unlock the large ones.
Starlink: how to think →
Diagonal adjacency, gap analysis, corner constraints.
How puzzle difficulty works →
What changes between Tier 1 and Tier 5 — pick your challenge level.
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