Zip asks for one continuous path through the grid, visiting numbered checkpoints in order and covering every cell exactly once. Moves go between cells sharing an edge. Reaching the last number is only a success if the rest of the board has already been covered. Respect any walls on the current board as well.
Read the board before drawing
Locate the first and last checkpoints, corners, walls and narrow connections. A corner has fewer possible neighbors than an open central cell. In the final route, each ordinary cell needs an entrance and an exit; the two endpoints need just one connection each. A non-endpoint cell with only two available neighbors must use both.
Distinguish an available grid edge from an edge actually used by the route. A square may have three geometric neighbors while only two remain available after considering walls or already occupied cells. Review that count whenever a new segment narrows the unused area.
A complete teaching route
The following 3-by-4 exercise is constructed for this guide. There are no walls. The numbers in the first diagram are checkpoints; dots are unnumbered cells. The second diagram shows visit order, not extra checkpoints.
CHECKPOINTS VISIT ORDER 1 · · 2 01 02 03 04 · · · · 08 07 06 05 3 · · 4 09 10 11 12
Every consecutive visit shares an edge, all twelve cells appear once, and checkpoints occur at visits 1, 4, 9 and 12. These are three separate checks. Passing the checkpoint check alone would not establish that the path covers the board.
After checkpoint 2, going straight down the right edge would reach checkpoint 4 before checkpoint 3. The complete route instead sweeps the middle row before entering checkpoint 3. A locally short move can conflict with the required global order.
Preserve access to pockets
Think of an unused group of cells as a room and its open connections as doors. If the path closes every door while cells inside remain unused, that branch cannot be completed. If a pocket has only one entrance and contains neither final endpoint nor the current path tip, entering it would require returning through the same connection, which would reuse a cell.
A narrow opening is a reason to inspect the area, not an automatic instruction to enter immediately. The checkpoint order may require a different approach. Ask how the route will enter, cover the pocket and leave, while preserving any checkpoints that must be visited later.
Reason from both ends
You can inspect the final checkpoint's neighbors before drawing anywhere near it. If its only possible approach runs through a corridor, reserve that corridor. This is a planning deduction; it does not mean you may physically visit the final checkpoint early.
Keep reserved connections distinct from a completed path. When two deductions compete for the same cell, revisit the earliest assumption. A route segment that looks elegant is not stronger evidence than a cell that would otherwise become unreachable.
Diagnose the first failed connection
- A stranded cell: find the move that removed its last possible entrance or exit.
- A closed loop: the route has sealed itself before completing the board.
- A checkpoint reached too soon: revisit the preceding segment rather than trying to skip the numbered cell.
- The last number reached with blanks remaining: the final approach was committed before the rest of the route was proved.
Undo to the most recent branching choice that caused the conflict. Repeatedly redrawing the same successful early segment adds work without testing a new possibility.
A useful practice habit
Before each uncertain turn, name what it preserves: a corner exit, a later checkpoint, or access to a pocket. After finishing, trace the path in order and count the visited cells. That produces a checkable explanation for the route instead of relying on its appearance.
Official play and board instructions: LinkedIn Zip.
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