Norinori Logic Puzzle
Exactly two shaded cells per region. Pick Shade or Dot, then mark cells so each region has exactly two shaded cells and every shaded cell has one shaded neighbour.
Tap or drag to mark. Tap again to clear. M switches mode.
How to play Norinori
Choose Shade or Dot
Shade fills a cell. A dot is a cell you already know stays empty. Tap a cell, or drag across cells, to place the mark. Tap a cell that already has that mark to clear it. A cell with the other mark takes the new one when you tap it.
Read the regions
Thick lines divide the board into regions. Thin lines are the cells inside a region. Each region needs exactly two shaded cells. A region can be any shape made of cells that share sides.
Pair every shaded cell
Every shaded cell shares a side with exactly one other shaded cell, so the shaded cells form pairs. The puzzle is finished when those shaded cells are the solution, even if some empty cells still have no dot.
Norinori is a shading puzzle on a board of regions. You shade some cells and leave the rest empty. Each region holds exactly two shaded cells, and those shaded cells come in pairs. You can play grids from 5×5 up to 8×8. 6×6 stops at medium. Every puzzle here has exactly one shaded set.
Rules
The board is an n×n grid divided into regions. Thick lines are the region borders. Thin lines are the cells inside a region. A region is a group of cells that share sides.
Shade exactly two cells in each region. Every shaded cell must share a side with exactly one other shaded cell. Three shaded cells in a row are not allowed, and a shaded cell with no shaded neighbour is not allowed. A pair can sit inside one region, or the two cells can belong to neighbouring regions, as long as each region still has two shaded cells.
A dot is a mark for a cell you already know is empty. Dots are optional. The puzzle does not ask you to dot every empty cell.
The puzzle is solved when the shaded cells are that unique set. Empty cells may still be blank. You do not have to place a dot on every empty cell.
Controls
Choose Shade or Dot under the board. Tap a cell, or drag across cells, to place that mark. Tap a cell that already has the mark to clear it. A cell that has the other mark takes the new one when you tap it. A drag follows the first cell: it places the mark on empty cells along the path, or it clears when that cell already has the mark. With a mouse, right-click places a dot, or clears a dot that is already there.
On a keyboard, the arrow keys move around the grid. Space or Enter places the selected mark, or clears it when the cell already has that mark. S or 1 shades the cell. X, D, E, or 2 places a dot. M switches Shade and Dot. Backspace, Delete, or 0 clears the cell.
A cell turns coral when a region has too many shaded cells, too few cells left to reach two, a shaded group is larger than a pair, or a shaded cell has no neighbour left. Press Hint for one step the rules already force, with a sentence saying why. Press Check when you want the board checked against the rules. Undo and Redo step through your moves, and Reset clears the board. When the shaded cells are the unique set, the board turns teal.
Techniques
Easy grids follow from one region at a time, plus the pair rule:
- Size 2: a region of two cells is shaded in both.
- Quota: only two cells in the region can still be shaded, so both are shaded.
- Room done: the region already has its two shaded cells, so the rest stay empty.
- Domino side: a finished shaded pair forces the cells beside it to stay empty.
- No partner: a cell with no legal partner stays empty.
- Must partner: a shaded cell with only one partner shades that cell.
Medium grids look at the pairs a region can still hold, and at how neighbouring regions limit those pairs. Hard grids try the other mark on one cell and keep the mark that does not break the board.
Beginner tips
Start with the smallest regions. A region of two cells is already a shaded pair, and the cells beside that pair often have to stay empty.
When a region already has two shaded cells, dot the rest of that region before you look for the next pair. Then check that no shaded cell touches more than one other shaded cell.
If you are new to Norinori, start with the daily 6×6 easy grid, or a 5×5 easy grid, and move up once the pairs feel natural.