Norinori Puzzle Strategy
After the first board, stop guessing cell by cell. Count each region, lock forced pairs, then forbid cells that would touch a finished domino.
A Reliable Norinori Solving Order
Scan in this order on every board. The six techniques below are how to execute each step, not a menu of optional tips.
- Find regions that can place their two black cells in only one way.
- Use finished pairs and board edges to force neighbouring cells white.
- Shade any pair that has only one remaining legal placement.
- Rescan cells beside completed dominoes.
- Ask which remaining cells in a region can still form a legal domino.
- Repeat until another pair becomes forced.
| Situation | Question to ask |
|---|---|
| A region has only two cells | Must both cells be shaded now? |
| A finished pair sits on an edge | Which neighbouring cells must stay white? |
| A region still needs two blacks | Which two cells can still form a legal domino? |
| A cell touches a finished domino | Is that cell forbidden because of adjacency? |
| A pair looks legal but uncertain | Can every other region still place two cells? |
| Two regions share a possible spanning pair | Does that pair leave both regions with a legal remainder? |
Technique 1: Finish Two-Cell Regions First
A region with only two cells is already a domino. Shade both. Then look at every neighbour: those cells cannot be shaded.
Larger regions still need exactly two black cells. If two cells are already shaded, the rest of that region stays white.
Controls and the four rules are on How to Play.
Technique 2: Use Adjacency Elimination
Once a domino is placed, no extra black cell may share its side. That often forces white cells along the pair.
If the rules are still unclear, return to How to Play.
Technique 3: Watch Region Remaining Counts
Ask how many black cells a region still needs. Zero means stop. Two and only two legal cells left means shade them.
Count remaining blacks in the region first. Then look at which two cells can still share a side.
Technique 4: Look at Edges and Corners
A cell on the edge has fewer neighbours. That limits how a spanning domino can leave the region.
An edge cell has fewer neighbours, so a spanning domino has fewer ways to leave the region. Do not treat a corner as automatically belonging to the nearest region.
Technique 5: A Local Pair Can Still Be Wrong
Two cells in a region can look legal and still block another region. If the rest of the grid cannot finish, undo the pair.
Technique 6: Check the Remaining Space
A finished pair can isolate leftover cells. Check whether each leftover region can still place exactly two blacks as a legal domino. If a pocket cannot, the last pair was wrong.
This is a necessary check, not a proof. A pocket can have the right number of cells and still have no legal pairing.
What to Do When You Get Stuck
If no pair looks forced, run this checklist before shading a speculative cell.
- Find the region with the fewest remaining legal pairs.
- Rescan every edge and corner.
- Inspect cells beside the most recently completed domino.
- From each difficult empty cell, ask which clue can own it.
- Compare the remaining candidates of one clue and keep their shared cells.
- Check whether leftover cells in a sealed pocket can still form legal pairs.
- If you already shaded a speculative pair, Undo it before adding another.
Hint reveals a correct cell; it does not promise a human-style explanation.
Practice Norinori Strategy
Use Unlimited to repeat one size until the counting habit is automatic, then move up a size.
Practice the order on Unlimited boards.