Duplicate shade network
Shade repeated entries without breaking the remaining white network.
Logic & rule checking
- Players
- 1–3
- Time
- 15–25 minutes
- Materials
- Printed puzzle, pencil and separate host key
Prepare
Copy the four rows printed on the player sheet. A row means a horizontal line, not a region. Numbers are fixed: you may shade a cell but cannot replace its digit. One person may solve while a second audits the three rules.
Follow the rule
Among unshaded cells, no number may appear twice within one row or one column. Equal numbers in different rows and columns are allowed. Shading a digit removes it from both its row and column comparisons.
Check each step
Shaded cells cannot share an edge. All unshaded cells must connect by edge steps; diagonal contact alone is insufficient. Do not require the shaded cells to form a network.
Worked example
The supplied board differs from a Latin pattern at A1 and C3. Test shading those two. Shading B1 as well would share an edge with A1, so that proposed shortcut fails even if it removes a repeated number.
Finish and adapt
Stop after checking every row, every column, shaded adjacency and a traced white route. Accept any arrangement meeting all rules; the example does not prove a unique solution. For support, cover other rows temporarily, then remove the cover for the connectivity check.
Purpose, observation and provenance
Within this activity: Shade repeated entries without breaking the remaining white network.
Check each constraint independently rather than compare only with the sample answer.
Our rules, examples and printable diagrams are separately prepared. The earliest inventor of the broader mechanism is not established here.
Official mechanism reference / 官方机制规则 — Background rules only; all small boards, examples and explanatory text are prepared for this kit. No publisher artwork is reproduced.
Free alternative: Copy the supplied grids, labels and cards onto reused paper. No specialist product is needed. Adults may prepare pieces or act as a scribe.
Printable materials
Preview at 100% scale, with browser headers and footers off. Cut with suitable help. Keep host keys separate. This is a manual tabletop kit, not an online opponent, automatic judge or solver.
Duplicate shade network · Player sheet
Before you begin
- Copy the four rows printed on the player sheet. A row means a horizontal line, not a region. Numbers are fixed: you may shade a cell but cannot replace its digit. One person may solve while a second audits the three rules.
- Among unshaded cells, no number may appear twice within one row or one column. Equal numbers in different rows and columns are allowed. Shading a digit removes it from both its row and column comparisons.
- Shaded cells cannot share an edge. All unshaded cells must connect by edge steps; diagonal contact alone is insufficient. Do not require the shaded cells to form a network.
| Proposed cells / boundaries | Constraint checked |
|---|---|
| ________ | ________ |
| ________ | ________ |
| ________ | ________ |
Duplicate shade network · Host key — keep separate
Shade A1 and C3; all remaining row/column entries are distinct and all 14 whites connect.
Read the rules as well as this example. Other valid solutions may exist for the puzzle boards. This key is not a claim of uniqueness or measured learning gains.
| Constraint / action | Evidence / correction |
|---|---|
| ________ | ________ |
| ________ | ________ |
| ________ | ________ |
| ________ | ________ |