Rules
The board is a grid with a few numbers. Empty cells have no number. Draw rectangles, across and down, that cover every cell and do not overlap. Each rectangle holds one number, and the number is the area.
- Rectangles cover the grid. Draw them across and down. They do not overlap, and together they cover every cell. Empty cells have no number.
- One number, and it is the area. Each rectangle holds exactly one number. That number is the width times the height. A square counts. A 1 covers its own cell.
- The numbers stay put. A printed number does not move. You draw around it.
- Finished. The grid is done when the rectangles fill it and every number matches its area. The numbers then add up to the number of cells.
A finished 4×4. Two of the areas are 2×2 squares, and a square is still a rectangle. The other two are full rows of 4. The borders are teal, the way a solved board looks, and the numbers stay dark. No dashes.
- Number
- Rectangle
- A break
A square is a rectangle. A 1-cell rectangle is legal when the number is 1. The numbers stay where they are printed. When the division is right, the borders turn teal and the numbers stay dark. Every Shikaku on PuzzleKite has one solution, and you can finish it by logic. The small windows in this guide are for the sentences. They are not sizes the play page deals.
First moves
Draw each printed 1, then a corner, an edge, or an interior number once only one rectangle fits.
A printed 1 Easy
A printed 1 covers its own cell and nothing else. Draw that cell. Do this whenever you see a 1. A 1 in a corner still uses this sentence. Hint does not call it a corner.
On a blank board the first rectangle is the left 1, even though that cell is also a corner. The ring is amber, the cell takes the hint wash, and the dash is amber. There is no violet rectangle yet. Hint says: “This 1 covers only its own cell.”
The same look draws the other 1 with the same sentence, then the bottom row as a corner. The picture rings only the first 1.
A 1 is first when no earlier number already has a single rectangle. The grid in section 2 draws a 2 before any 1, because those 1s sit later in the list. A 10×10 or 12×12 easy grid often opens on a corner rather than on a 1. Do not wait for a 1 that is not there.
A corner number Easy
A number in a corner often has one rectangle that fits. Draw that rectangle. It stays inside the grid, holds that number, and does not hold any other number. A corner 1 is the section above, not this one.
The left 2 is the left column. The top row would hold both 2s, so it is not a rectangle for either of them. Hint says: “This number sits in a grid corner, and only one area fits it.”
The next hint is the same sentence on the right column. The picture rings only the left one.
The finished picture in the rules opens on this sentence too: the top row of 4 is a corner. That board is larger. The pair here is the whole idea.
A number on the edge Easy
A number on the edge, and not in a corner, is the same idea. Count the rectangles of the right area that stay on the board and leave every other number outside. When one remains, draw it. A column that is taller than the grid is not a candidate.
The 4 in row 1, column 2 sits on the edge and is not in a corner. Its rectangle is the whole top row. A column of four does not fit in three rows. Each 2×2 that contains this 4 also contains one of the other 4s, so those 2×2s are not candidates. Hint says: “This number sits on the grid edge, and only one area fits it.”
The picture draws only the top row. The next two hints are:
- With the top row drawn, the 4 on the left is the 2×2 under it. Hint still calls that an edge.
- The last 4 is then the 2×2 on the right. That sentence is the one in the next section. The picture stops at the top row.
Placing that rectangle often leaves the next number with one rectangle. The how-to calls that a chain. Hint still uses the edge sentence, or the only-one-rectangle sentence, for each step. There is no separate chain sentence. The 2×2 on the left, drawn while the top row is still missing, is unfinished, and Hint still asks for this top row.
Only one rectangle Easy
An interior number can also have one rectangle that fits its area and leaves every other number outside. Draw it. This can be the first mark. It can also be the mark you get after a corner or an edge, which is the third hint on the board in section 2. A printed 1 is this kind of single too, and Hint uses the 1 sentence for it instead.
The center 2 is interior, and its rectangle is the pair to its left. The pair to the right would hold both 2s in that row. The pair upward would hold the top 2. The pair downward would hold the 1. The top 2 still has two horizontal pairs, so it is not a single yet. Hint says: “Only one area matches this number and leaves every other number outside.”
The three 1s are singles already. They come later because they sit lower on the grid. The next hints are the right-hand column of 2, then the top pair, then the three 1s. The picture rings only the center pair.
This is an easy step. Some easy grids never say it. The daily 7×7 easy grids do.
An easy grid finishes from a printed 1, a corner, an edge, and sometimes one interior rectangle, medium adds a cell only one number can reach, hard adds a shared cell or a hole and may need only one of those, and the deeper try after the hard sections is a real Hint sentence the grids on this site do not ask for.
Only one number can reach Medium
Look for an empty cell that only one unfinished number can cover. That number’s rectangle has to include the cell, so any area of that number which misses the cell is dropped. Draw the rectangle that remains. The number’s own cell does not do this when every one of its areas already covers it.
Row 1, column 2 is empty, and only the 5 can cover it, and only with the top row. The other area of the 5 is the column from row 1 to row 5 in column 3. It misses that cell, so it is dropped. The 5’s own cell, row 1 column 3, sits in both areas and drops nothing by itself. Hint says: “Only one number can reach this cell, so its area has to cover it.”
Row 1 column 1 is also reachable by the 2. Row 1 columns 4 and 5 are reachable by the 6. Do not say the whole row is unreachable by other numbers. The next hint is the edge on the 2 at the left, not another cell of this kind. The picture does not draw it.
Medium grids need this. A given medium grid may still open on an edge or on a single rectangle. This step comes when those stall. After the rectangle is drawn, the next number often gets a cheaper edge or only-one-rectangle sentence. Do not expect the next hint to stay on this one.
Hard moves
When every rectangle a number can still be covers the same cells, those cells belong to it. When a rectangle would leave a cell no number can take, do not use it.
Cells every area covers Hard
If every rectangle that a number might still be covers the same extra cells, those cells belong to that number. Any other number’s rectangle that uses one of them is dropped. You may not know the first number’s shape yet. You draw the other number, the one that just lost its last alternative.
The sentence does not say which number owns the shared cells. The picture has to. The highlighted rectangle is the one you draw. The shared cell can sit outside it.
Both areas of the 4 cover row 3, column 1: the bottom row, and the block of rows 2–3, columns 1–2. That cell is washed, and it is not part of the rectangle you draw. The left 3 cannot be the column any more, so it is the top three cells. The 4’s own cell kills nothing. The right 3 and the 2 have no extra shared cell that kills a neighbour. Hint says: “Every possible area for this number covers these cells, so they belong to it.” The number in that sentence is the 4. The rectangle on the board is the left 3.
The left 3 sits in a corner, and it had two rectangles until row 3 column 1 was spoken for, so the sentence is still this one. The next hint is the corner on the right-hand column. The picture does not draw it, and it does not draw the 4.
Hard grids add this. Not every hard hint says it. A 5×5 hard grid can open on it. Some hard grids finish with the hole in section 4 and the walk never says this sentence. One 5×5 hard grid records the shared cells and never shows this sentence or the hole sentence, because a later step names those cells another way. A hard grid does not have to open here.
An area that leaves a hole Hard
Try a rectangle that still fits the number. If drawing it leaves a cell that no number can take, that rectangle is not used. The cell may be another number’s own cell, once that number has no rectangle left. Drop the bad area and draw the one that remains.
This is a hard step. Some hard grids say it, and a 6×6 hard grid can open on it. The 5×5 hard grids do not say it. They use section 4. The daily grid does not need it. The picture of the hint is the rectangle you keep. The worked try is one rectangle you do not keep. The sentence is about that unused rectangle. The button does not draw the try.
The lower 3 keeps row 3, columns 1–3. It had three areas. The row survives. Both columns die in the same pass, after the upper 3’s columns have already died. Hint says: “This area leaves a cell no number can take, so it is not used.” The ring is on the row you keep.
Once this row is drawn, the next hint is the corner on the bottom row of the 4, not another hole. This grid also has shared cells, and the walk never says that sentence. The picture does not add it.
The column that strands a 3
The same digits, still blank. The preview rectangle is the try: column 3 from row 1 to row 3. The caption calls it the try. There is no amber ring.
The dashed violet rectangle is the try. The violet ring is the upper 3, the cell nobody can take. It is not a Check error. On the real board this column is never placed, so nothing here is red.
- The upper 3 has a column in column 2, from row 1 to row 3. It covers row 3, column 2. The only area that can still take the empty cell at row 3, column 1 is the 4’s block, and that block also needs row 3, column 2. Row 3, column 1 is left with nobody. That column is not used.
- The upper 3’s other column runs from row 2 to row 4 in column 2. It covers a cell of both areas of the 4. The 4 is left with nothing, and row 3 column 1 and row 4 column 1 are uncovered. That column is not used.
- Two rows are left for the upper 3: row 2, columns 1–3, and row 2, columns 2–4. Both include row 2, column 3.
- The try is column 3 from row 1 to row 3. It covers row 2, column 3, so both of those rows die. The upper 3’s own cell, row 2 column 2, has no rectangle. The lower 3’s other column leaves the same cell. The violet ring is that cell. It is not red: the column was never placed.
- Before those first two columns are discarded, the try does not yet leave a hole, because the upper 3 still has them. The row that stays, row 3 columns 1–3, does not cover row 2 column 3. That is the rectangle in the other picture.
An easy grid finishes from a printed 1, a corner, an edge, and sometimes one interior rectangle, medium adds a cell only one number can reach, hard adds a shared cell or a hole and may need only one of those, and the deeper try after the hard sections is a real Hint sentence the grids on this site do not ask for.
Only one area survives Not dealt
Sometimes every immediate check still allows two rectangles, and only a short chain of ordinary singles shows that one of them breaks. Try each one. Follow the singles. Do not start a second guess inside the first. If one side leaves a number with no rectangle, draw the other side.
This sentence is real, and the grids on this site do not need it. Easy, medium, and hard finish with the earlier sections. The figure is a 4×4 that would not be dealt, so do not hunt for it on a 7×7 hard grid.
The top 2 has two pairs. The left pair is the one that can be drawn. Hint says: “Only one area for this number can be drawn without a contradiction.” Once this pair is drawn, the rest is singles: the edge on the 4, the edge on the right-hand 3, the corner on the top-right 2, the only-one-rectangle on the upper 3’s row, and the edge on the bottom 2. The next hint is the edge on the 4, not another try. The picture does not draw those.
The other pair dies in the singles
The try is row 1, columns 2–3, plus the two rectangles the singles write before the grid breaks. All three are the try. The upper 3’s last row is not drawn: placing it is the step that breaks, so it was never a finished rectangle.
Three preview rectangles, and no amber ring. The violet ring is the 4 that runs out of rectangles. Row 1 column 1 is the same break on an empty cell. Neither is red, because the try was never placed.
- The try covers row 1, column 3, so the top-right 2 cannot be the short row beside it. It becomes the column in column 4, rows 1–2. That column is drawn with the try.
- The new column covers row 2, column 4, so the right-hand 3 cannot be its tall column. It becomes the row in row 3, columns 2–4. That row is the third preview rectangle.
- The upper 3’s downward column already leaves row 2, column 3 with nobody, even on the blank grid. Its row across row 2, columns 2–4, now overlaps the new column. The only area left is row 2, columns 1–3.
- That last row covers row 2, column 1, which sits in the 4’s left column. The right-hand 3’s new row already covers row 3, column 2, which sits in the 4’s block. The 4 has no rectangle. Row 1 column 1 and row 4 column 1 are empty cells with nobody either. The violet ring is the 4. None of this is red, because the try was never placed. The upper 3’s row is the step that breaks, so it is not drawn.
The try itself leaves no hole and no number with nothing. The singles after it are what break. That is why this is not section 4.
An easy grid finishes from a printed 1, a corner, an edge, and sometimes one interior rectangle, medium adds a cell only one number can reach, hard adds a shared cell or a hole and may need only one of those, and the deeper try after the hard sections is a real Hint sentence the grids on this site do not ask for.
Common mistakes
Red shows only while error highlight is on. The conflicting rectangle takes the red fill and the red border. The wash and the red digit are only the cited cells. A number that is not cited stays dark, including on a solved board. Solved rectangles turn teal. The digits stay dark. They do not turn white.
The corner 4 is drawn as two cells. The whole rectangle is red. The wash and the red digit are only on the 4. The empty cell is not cited. Hint still asks for the real top row, and the picture does not draw it.
One rectangle holds both 4s on the left. There is no second rectangle on the board. Both digits are red, and both cells are washed. Hint still asks for the real top row.
A one-cell rectangle on an empty cell has nothing to match. The cell is red. There is no digit to turn red. Hint still asks for the real top row.
The top row matches the solution, so it stays violet. The later rectangle is red on all four of its cells, not only the two it shares. The 4 inside it turns red. The corner 4 stays dark. Hint moves on to the 2×2 on the left, and the picture does not draw that one.
This 2×2 holds the interior 4 and has area 4, so it breaks nothing. It is not one of the four solution rectangles. Nothing is red. Hint does not erase it. Hint still asks for the top row.
What to play next
Once a printed 1 and a corner feel quick, move up a setting. Each one adds a new idea.
- EasyA 1, then one rectangleThe daily size. Draw each 1, then the corner and the edge that have one rectangle, and an interior number once it has one rectangle too. A 5×5 easy grid is the same lesson on a smaller board.Play Easy →
- MediumA cell only one number can reachWhen those singles stall, find a cell only one number can reach. That number’s rectangle has to cover it.Play Medium →
- HardA shared cell, or a holeWhen a cell belongs to every area a number has left, give it to that number. When a rectangle would leave a cell nobody can take, do not use it. A given hard grid may need only one of those.Play Hard →
5×5 through 10×10 come in easy, medium, and hard, on the play page and in print. 12×12 at easy and medium is print only. Try 5×5 easy when you want the same easy lesson on a smaller board.
The daily puzzle is a 7×7 easy grid: today’s Shikakuor the same setting in the game. Those grids finish with a 1, a corner, an edge, and a number that has one rectangle. Print packs are at printable Shikaku. A 5×5, 6×6, or 7×7 sheet holds four puzzles. An 8×8, 9×9, or 10×10 sheet holds two. A 12×12 sheet holds one. Large print is one. The answer key starts on its own page, with the numbers kept and thick borders where areas meet.
- GuideNurikabeGrow each island to its number and keep one sea.
- GuideHitoriShade repeats, never side by side, keep white connected.
- GuideLight UpLight every cell. Start beside the 4s and 0s.
- GuideNonogramsOverlap long clues, cross the gaps, and read the crossing line.
- GuideHashiCount bridges, never cross, connect every island.
- GuideSudokuRows, columns and boxes, from singles to triples.
- GuideBinairoSpot pairs, fill the gaps, balance every line.
- GuideStar BattleOne or two stars in every row, column and region.
- GuideSlitherlinkDraw one loop. Start from the 0s and the 3s.
- GuideKakuroOne-way sums first, then short runs and longer lists.
- GuideKiller SudokuCage sums and house totals do the work.
- GuideFutoshikiSigns first, then chains, one home in the line, and a one-cell try.
- GuideMasyuTurn on black pearls, go straight through white ones.