Rules
Norinori is a shading puzzle. The board is a square grid. Thick lines are the borders of the regions. Thin lines are the cells inside a region. Each region is a group of cells that share sides, and each region holds exactly two shaded cells. Every shaded cell shares a side with exactly one other shaded cell, so the shades come in pairs. A pair can sit inside one region. It can also cross a border, one cell in each region. The two shaded cells that belong to the same region do not have to touch. You shade a cell, or you mark it with a dot when you already know it is empty. Dots are optional. The puzzle is finished when the shaded cells are that one set, even if some empty cells are still blank. Play is 5×5, 6×6, 7×7, and 8×8. 5×5, 7×7, and 8×8 are easy, medium, and hard. 6×6 is easy and medium. The daily puzzle is a 6×6 easy grid. People also look this up as a norinori puzzle.
Hitori also shades cells. There a shaded cell never shares a side with another shaded cell. Here every shaded cell shares a side with exactly one.
- Thick lines are regions. The board is a square grid. Thick lines are the borders of the regions. Thin lines are the cells inside a region.
- Two shaded cells. Each region is a group of cells that share sides, and each region holds exactly two shaded cells.
- Shades come in pairs. Every shaded cell shares a side with exactly one other shaded cell. A pair can sit inside one region, or one cell in each of two regions.
- Dots are optional. A dot is a cell you already know is empty. The puzzle is finished when the shaded cells are that one set, even if some empty cells are still blank.
Shades sit at row 1 columns 1–2 and 4–5, row 3 columns 1, 3, and 4, row 4 columns 1 and 5, and row 5 columns 2–3 and 5. Everything else stays blank. On this grid every pair sits inside one region. A pair may still cross a border. The hard-grid figures later in this article show that. The frame is the solved frame. The shades are the solved teal. Region borders are teal. No dots. No yellow ring. A printed answer fills the shaded cells and leaves empty cells blank. It does not print dots.
- Shade
- Dot
- Region border
- Broken shade
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 with the other mark takes the new one when you tap it. A drag follows the first cell: it places the mark, or it clears when that cell already has it. With a mouse, right-click places a dot, or clears a dot that is already there. Arrow keys move and stop at the edge. The first arrow, when nothing is selected, selects the top-left cell. Space or Enter places the selected mark, or clears it when the cell already has that mark. S or 1 shades. X, D, E, or 2 places a dot. M switches Shade and Dot. Backspace, Delete, or 0 clears the cell. There is no cycle through the marks.
While the puzzle is unfinished, the line under the board reads: "Tap or drag to mark. Tap again to clear. M switches mode."
Press Hint for one step the rules already force, with a sentence saying why. Hint lights the cells it writes. Press Check when you want the board checked. A legal unfinished board gets "No mistakes so far. Keep going!" A broken board gets "A region has the wrong shaded count, a shaded group is not a pair, or a shaded cell stands alone. Look for the marked cells." Hint on a broken board gets "This board has a mistake, so there is no hint yet." If Hint finds nothing on a legal board, it says "No forced cell from here. A shaded cell or a dot may be in the wrong place, so try Check or Undo." Undo and Redo step through the moves. Reset clears every shade and every dot you placed. The regions stay. When the shaded cells are the unique set, the board turns teal. The dialog title is "Solved!" The dialog body is "Each region has two shaded cells, and every shaded cell has one shaded neighbour." The Mistakes counter counts how many times Check found a broken board. It is not a score.
The ideas, in the order you can use them, are a region of two cells, a region with only two cells left to shade, a region that already has its two shaded cells, the cells beside a finished pair, a cell with no legal partner, and a shaded cell with only one partner. Medium grids then 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. The pairs a region can still hold are the two shaded cells of that region. They do not have to touch. The neighbour rule is separate: every shaded cell has exactly one shaded neighbour. The button writes one technique and stops.
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. With error highlighting off, none of that coral is drawn. The picture of a finished grid in this article leaves the empty cells blank. A printed answer does the same. Dots are not printed.
- Undo
- Redo
- Reset
- Hint
- Check
The region
Each region holds two shaded cells. A region of two cells is shaded in both. When only two cells in the region can still be shaded, those two are shaded. When the two are already shaded, the rest of the region stays empty. Those two cells do not have to touch each other.
Two cells Easy
A region of two cells is shaded in both. You do not choose which one. On this grid the left-hand pair in rows 3 and 4 is that region, so row 3 column 1 and row 4 column 1 are shaded. They share a side. The press writes those two cells and nothing else.
This grid has two more regions of two cells. The next press shades row 4 column 5 and row 5 column 5. The press after that shades row 1 column 4 and row 1 column 5. Those presses are not drawn. One grid in the hard section has no region of two cells, so it does not open this way. The toast is "This region has two cells, so both are shaded."
Violet shade and a yellow ring on row 3 column 1 and row 4 column 1. There is no amber wash under the shade. The two cells are pulled together. Every other cell stays ordinary. The grid is still unfinished, so the toast shows. Hint says "This region has two cells, so both are shaded."
Only two left Easy
Once a region is not a two-cell region, the same count still forces what is left. If only two cells in the region can still be shaded, both are shaded. On this grid the top-left region is row 1 columns 1, 2, and 3. The cell beside a finished pair has already dotted row 1 column 3, so row 1 columns 1 and 2 are the two that remain. The press shades both. They share a side.
On this grid those dots are the previous press, and this shade is the fifth press. The article still teaches the region's count first. The toast is "Only two cells in this region can still be shaded, so both are shaded."
The last press of a grid is often this same sentence, and it finishes the grid, so the toast is replaced by the solved dialog. This figure does not finish. A press that shades one cell, because the other shade is already there, uses the same toast. That shape is not drawn.
Violet and a yellow ring on row 1 columns 1 and 2. They pull together. There is no amber wash under the shade. Row 1 column 3 stays a dot. It is not rewritten. The earlier shades and the two dots stay ordinary. They are not in the write. Hint says "Only two cells in this region can still be shaded, so both are shaded."
Already two Easy
When a region already has its two shaded cells, the cells still open in that region stay empty. The two shaded cells do not have to touch. On this grid the left-hand column of three is one region: row 3 column 1, row 4 column 1, and row 5 column 1. Row 3 column 1 and row 5 column 1 are already shaded. Row 4 column 1, the cell between them, is empty. Row 3 column 1 takes its partner from the next region, at row 3 column 2. Row 5 column 1 has not taken its partner yet. The region is still done, so the press dots row 4 column 1 and nothing else.
This sentence sits with the easy ideas, and the button can say it on an easy puzzle. None of the easy grids in this set need it, and none of the 6×6 grids need it. The toast is "This region already has its two shaded cells, so the rest stay empty."
Amber wash, a yellow border, and a yellow ring on the new dot at row 4 column 1. The two shades of the region stay ordinary violet. They do not touch, so they are not pulled together. They are not in the write. The grid is still unfinished. Hint says "This region already has its two shaded cells, so the rest stay empty."
The pair
Every shaded cell shares a side with exactly one other shaded cell. A finished pair forces the cells beside it to stay empty. A cell with no legal partner stays empty. A shaded cell with only one partner shades that cell, and the partner may sit across the border.
Beside the pair Easy
A shaded pair is finished when the two cells share a side. Every other cell beside that pair stays empty. On this grid row 1 columns 4 and 5 are a two-cell region, so they are both shaded. Row 1 column 4 still touches row 1 column 3 and row 2 column 4. Those two cells are in other regions. The press dots both. Row 1 column 5 touches row 2 column 5 as well. That dot is a later press. The sentence is the same.
The pair itself is not rewritten. The toast is "This shaded pair is finished, so the cells beside it stay empty."
A later press can dot one cell, or three. On another easy grid, one press dots row 3 column 3, row 2 column 2, and row 2 column 4 beside the pair at row 1 column 3 and row 2 column 3. That press is not drawn.
Amber on the two new dots, row 2 column 4 and row 1 column 3. Row 1 columns 4 and 5 are already shade and are not in the write, so they stay ordinary violet, still pulled together. The other shades stay ordinary. Row 2 column 5 stays unknown. Hint says "This shaded pair is finished, so the cells beside it stay empty."
No partner Easy
A cell stays empty when no neighbour can be its partner. On this grid row 3 column 2 has a cell on every side, and every one of those cells is already a dot. There is nowhere for a partner to go, so row 3 column 2 is a dot too. The press writes that one cell.
The next press on this board is the corner, row 5 column 5. Both of its neighbours are already dots, so it is a dot as well. Same sentence. That corner is not drawn. The toast is "This cell has no legal partner, so it stays empty."
A 5×5 easy grid can finish without this sentence. The daily 6×6 easy grid finishes without it. A 7×7 easy grid says it. This 5×5 easy grid says it near the end. The button on an easy puzzle returns it, because the sentence is in the first group.
Amber on the new dot at row 3 column 2 only. The four neighbours, row 2 column 2, row 3 column 1, row 3 column 3, and row 4 column 2, are already dots and stay ordinary. They are not rewritten. Three cells stay unknown. Hint says "This cell has no legal partner, so it stays empty."
The only partner Easy
A shaded cell that does not yet touch another shade must take a partner. When only one neighbour can be that partner, that neighbour is shaded. It may sit in the next region. On this grid row 3 column 2 is shaded, and the cells above it, below it, and to its right are already dots. The only open side is row 3 column 1, across the border. The press shades row 3 column 1.
Row 3 column 1 belongs to the three-cell region in the left column. That region's other shade is row 5 column 1, which does not touch row 3 column 1. The previous section's "already two" is what dots the cell between them. This press does not. The toast is "This shaded cell has only one partner, so that cell is shaded."
This sentence sits with the easy ideas, and an easy puzzle returns it. None of the easy grids in this set say it.
Violet and a yellow ring on row 3 column 1. It pulls toward row 3 column 2, across the region border. There is no amber wash under the shade. Row 3 column 2 stays ordinary violet. The dots on row 2 column 2, row 3 column 3, and row 4 column 2 stay ordinary. Two other shaded cells on this grid still have more than one open side, so they are not this press. Hint says "This shaded cell has only one partner, so that cell is shaded."
The pairs still open
List the ways a region can still place its two shaded cells. One way writes that pair. Neighbouring regions can leave only one way. A cell that is in every remaining way is shaded. A cell that is in none of them stays empty. On the grid where the one way left appears, the neighbour sentence was the earlier press. The article still teaches the one way first.
One way left Easy
Count the ways a region can still place its two shaded cells. Each shaded cell, including those two, still needs exactly one shaded neighbour. The two cells of the region do not have to touch. When only one of those ways is left, the press shades that pair and dots the rest of the region.
On this grid the region is row 4 columns 2, 3, and 4, plus row 5 columns 1 and 2. Row 4 column 2 and row 5 column 1 are already dots. The only way left is row 4 column 4 and row 5 column 2. Those two do not share a side. Row 4 column 4 already touches the shade at row 4 column 5, in the next region. Row 5 column 2 already touches the shade at row 5 column 3, in that same next region. Row 4 column 3 cannot join either of them without giving one of those shades a second partner, so the press dots row 4 column 3 as well.
The how-to files this look with the pairs a region can still hold. The sentence is in the first group, and an easy puzzle returns it. It pressed once in this set, on this medium grid. On this grid the neighbour sentence was the previous press. The article still teaches this one first. The toast is "This region has only one way to place its two shaded cells."
Amber on the new dot at row 4 column 3. Violet and a yellow ring on row 4 column 4 and row 5 column 2. Those two shades do not touch, so they are not pulled together. Row 4 column 4 pulls toward the existing shade at row 4 column 5. Row 5 column 2 pulls toward the existing shade at row 5 column 3. Those two existing shades are not in the write, so they have no yellow ring. Row 4 column 2 and row 5 column 1 are already dots and stay ordinary. Hint says "This region has only one way to place its two shaded cells."
What the neighbours leave Medium
A region can still have several ways to place its two shaded cells until the regions next to it are taken into account. When the neighbours leave only one way, the press shades that pair and dots the rest of the region.
On this grid the region is row 1 columns 4 and 5, and row 2 column 5. Row 2 column 4, the fourth cell of the region, is already a dot. Three ways are still legal if you look at this region alone: the two cells of row 1, or either of those cells with row 2 column 5. The region below has only one pair left, and that pair shades row 3 column 5, directly under row 2 column 5. Row 2 column 5 cannot be one of this region's shades, because it would then touch row 3 column 5 as well as its own partner. The only way left is row 1 columns 4 and 5. The press shades those two and dots row 2 column 5.
The toast says "The neighbouring regions leave only one pair here, so those two cells are shaded." The dot is part of the same press. An easy puzzle returns this hint. A blank easy walk does not say it. Two other regions on this same grid are also down to one pair. The next press writes one of them. The sentence is the same. That press is not drawn.
Violet and a yellow ring on row 1 columns 4 and 5. They share a side, so they pull together. Amber on the new dot at row 2 column 5. Row 2 column 4 is already a dot and stays ordinary. Row 3 column 5 is still unknown. It is not in this write. Six cells stay unknown. Hint says "The neighbouring regions leave only one pair here, so those two cells are shaded."
Every pair covers it Medium
Sometimes several ways remain, and every one of them uses the same cell. That cell is shaded. The press does not yet choose the other cell.
On this grid the region is row 3 column 2, row 4 column 2, and row 4 column 3. Two ways remain. One shades row 4 columns 2 and 3. The other shades row 3 column 2 and row 4 column 3, and those two do not even share a side. Both ways shade row 4 column 3. The way that leaves row 4 column 3 empty would shade row 3 column 2 and row 4 column 2, and each of those touches a cell the region on the left still has to shade. That way is gone. The press shades row 4 column 3 only.
This was already true before the three dots at the start of the grid. The button dots a cell in the top region first, because it looks there first. The figure is the press that shades row 4 column 3. The next press shades row 5 column 1, same sentence, in the left-hand column. That press is not drawn. The toast is "Every remaining pair in this region covers this cell, so it is shaded."
An easy puzzle returns this hint. A blank easy walk does not say it. A 5×5 medium grid and a 6×6 medium grid in this set do not say it. Some larger medium grids do.
Violet and a yellow ring on row 4 column 3 only. There is no amber wash under the shade. Row 3 column 2 and row 4 column 2 stay unknown. The three dots stay ordinary. Hint says "Every remaining pair in this region covers this cell, so it is shaded."
No pair covers it Medium
A cell stays empty when no remaining way to place the region's two shaded cells uses it. On this grid the top region is the whole first row plus row 2 columns 1, 2, and 5. Many pairs of those cells look legal on their own. Once the regions beside it are allowed for, every pair that is still possible stays on the left: columns 1 to 3, and those three cells of row 2. Row 1 column 4 is in none of them, so it is a dot.
Row 1 column 5 is the next press, and row 3 column 3 is the press after that. Same sentence. Those presses are not drawn. The toast is "No remaining pair covers this cell, so it stays empty."
This grid has no two-cell region, so this dot is the first press. The article still teaches the region and the pair first. An easy puzzle returns the hint. A blank easy walk does not say it, and a 5×5 medium grid does not say it.
Amber on the new dot at row 1 column 4 only. Row 1 column 5 stays unknown. It is the next press. The grid is still unfinished. Hint says "No remaining pair covers this cell, so it stays empty."
One cell, both ways
Try the other mark on one cell. The mark that cannot be finished is dropped, and the mark that can be finished stays. Both marks can also force the same cell somewhere else. On these grids the button does not say that second sentence.
The other mark fails Hard
When the earlier sentences stop, try the other mark on one cell. One of the two marks cannot be finished. The other can. The press writes the mark that can. On this grid a dot at row 1 column 1 cannot be finished. A shade can. The press shades row 1 column 1. It does not fill the rest of the grid. One cell is still a single step, so the toast shows.
The same sentence can write a dot. On the other 5×5 hard grid, one press dots row 3 column 4, because a shade there cannot be finished. The next press dots row 4 column 4. The first of those dots is the cite. Neither is drawn. The toast is "The other mark contradicts the board, so this mark stays."
Do not walk every later cell of the failed mark. The failed mark is the one that cannot be finished. An easy puzzle returns this hint. A blank easy walk and a blank medium walk do not say it. There is no 6×6 hard grid.
Both marks can also force the same cell somewhere else: "Both assumptions force this same mark." The how-to does not separate that sentence. On these grids the button does not say it. There is no separate picture.
Violet and a yellow ring on row 1 column 1. There is no amber wash under the shade. The dots and the earlier shades stay ordinary. Row 1 column 2, the cell that will pair with it, stays unknown and ordinary. Nineteen cells stay unknown. Hint says "The other mark contradicts the board, so this mark stays."
Common mistakes
Check paints a broken rule. Hint will not explain a board that is already broken. The toast is "This board has a mistake, so there is no hint yet." A wrong shade or a wrong dot can also sit there with no coral at all. Then Check says "No mistakes so far. Keep going!" and Hint still offers the next real step. The wrong mark stays unless that step writes the cell.
Five pictures, all on the same blank grid as the two-cell region. No amber on the four broken ones. The quiet one may show the opening two-cell region, because the board is legal. Coral is the cells the rule names. A region with too many shades paints those shades, not the whole region. A region that cannot reach two paints every cell of the region. A shaded run paints the run. A shade with no neighbour left paints that one cell.
Shades at row 2 column 1, row 2 column 3, and row 5 column 4. They do not touch, so there is no run. Those three shades are coral. The rest of the region stays ordinary. Nothing is amber. Hint on this board says "This board has a mistake, so there is no hint yet."
Row 1 columns 2, 3, and 4 are shaded. The middle cell has two shaded neighbours. The run crosses the border between the top-left region and the two-cell region at row 1 columns 4 and 5. The top-left region has exactly two shades, so it is not over. The two-cell region has one shade, so it is not short. The run is coral. Nothing is amber. Shading row 5 columns 1, 2, and 3 would be both too many shades and a run. That stack is not drawn. Hint says "This board has a mistake, so there is no hint yet."
Row 5 column 3 is shaded, and row 4 column 3, row 5 column 2, and row 5 column 4 are dots. The shade has no shaded neighbour and no unknown neighbour. Only that shade is coral. The three dots are not coral. The large region still has other unknowns, so it is not short. Nothing is amber. A dot on one cell of a two-cell region marks both cells of that region, because the region can no longer reach two shades. That is not a cell standing alone. Unknowns beside a shade are unfinished, not this error. Hint says "This board has a mistake, so there is no hint yet."
Row 1 columns 4 and 5 are both dotted. That region has two cells, so it cannot reach two shades. Both cells are coral, the whole region. Nothing is amber. Hint says "This board has a mistake, so there is no hint yet."
The four pictures above are what Check paints. A wrong mark Check does not see yet is the other picture. With error highlighting off, the extra shades, the run, the lone shade, and the short region paint nothing coral.
The shade at row 2 column 1 is empty in the solution. One shade does not put the large region over two, and it does not touch another shade. No coral. Check says "No mistakes so far. Keep going!" The amber is the opening two-cell region, row 3 column 1 and row 4 column 1, and this shade is not among them. The wrong shade stays. A dot at row 5 column 2, which is shaded in the solution, is also quiet. The opening press does not name it, so the dot stays. A dot on a cell the press does name is replaced.
What to play next
Easy grids follow from one region at a time, plus the pair beside it. A two-cell region, the cells beside a finished pair, and a region with only two cells left. Start there. The daily puzzle is a 6×6 easy grid, and that size finishes from those sentences. It does not need a cell with no partner. A 5×5 easy grid can finish without that sentence too. A 7×7 easy grid says it. A region that is already done, and a shaded cell with only one partner, are in that same first group. The easy grids in this set do not need them. Medium grids add the pairs one region can still hold, and the way a neighbouring region leaves only one pair. The earlier sentences still come first, and a medium grid still opens on a two-cell region. Hard grids try the other mark on one cell. One 5×5 hard grid has no two-cell region, so it opens on a cell no remaining pair covers. 6×6 has no hard grid.
- Easy8×8Those sentences on a larger grid. Some of these grids also dot a cell with no partner.Play 8×8 →
- Medium5×5The pairs one region can still hold, and a region the neighbours reduce to one pair.Play 5×5 →
- Medium7×7The same, and on some grids a cell every remaining pair covers, or a cell none of them cover.Play 7×7 →
- Hard5×5The other mark on one cell. One of these grids opens on a cell no remaining pair covers.Play 5×5 →
A printed answer fills the shaded cells and leaves empty cells blank. Dots are not printed. Four 5×5, 6×6, or 7×7 grids share a sheet. Two 8×8 grids share a sheet. There is no 10×10 and no 12×12. The printable page is Norinori packs.
There is no guide-sized seed to open. The boards above are teaching boards.