Sudokus
Eighteen grids, all of them mine.
For years I drew my own sudokus, with regions other than the usual three-by-three blocks. There is only one rule, and it holds everywhere: in every region each sign must appear exactly once. What counts as a region is up to me.
Every puzzle below was made by my own generator and checked to have exactly one solution. Solve one of them and you may be almost certain that nobody before you has solved the same riddle.
They run from small to large, and within each size from regular to irregular. So start at the top if you are still learning the game, and at the bottom if you want to see how far I went.
The puzzle pages themselves are in Dutch only: the board names every region out loud, and I have not translated those names yet.
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Four signs
Size: 4 × 4 Signs: + X 0 =
Sixteen squares, four signs, and not a digit among them: +, X, 0 and =. That changes nothing about the rule — every sign must appear exactly once in each row, each column and each two-by-two block. The fact that the signs mean nothing is the whole point: you are not counting here, you are ruling out. It is the smallest grid I made, and the quickest way to explain the game to someone.
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Around a cross
Size: 5 × 5 Signs: A B C D E
Five by five, with the letters A to E instead of digits. The five regions are not squares: a cross of five cells sits in the middle of the grid, and the four other regions fold around it into the corners. Watch the cells where a corner region touches the cross — that is nearly always where the first moves are. If you are used to three-by-three blocks, you will have to learn to look again.
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Six in blocks
Size: 6 × 6 Signs: 1 2 3 4 5 6
Six signs, and the blocks are no longer squares but rectangles three wide and two high. Six of them fit in the grid: two side by side, three above one another. Nothing else changes — row, column, rectangle, every sign exactly once. This is the smallest format that already gives you the real sudoku feeling.
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Six with diagonals
Size: 6 × 6 Signs: 1 2 3 4 5 6
The same grid as six in blocks, with two regions added: both corner-to-corner diagonals. Every digit must appear exactly once on each diagonal as well. That is two extra conditions on twelve cells, and you notice it at once — the four corners and the middle settle far sooner than you are used to. The diagonals have their own fill and their own hatching, because colour on its own is not information.
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Six, lying and standing
Size: 6 × 6 Signs: 1 2 3 4 5 6
Here two divisions lie on top of one another. Every sign must appear exactly once in the black-bordered rectangle three wide and two high, and exactly once in the coloured rectangle two wide and three high. So every cell belongs to two rectangles at the same time, and those two only half overlap. The grid is small; the ruling out is not.
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Seven seats
Size: 7 × 7 Signs: 1 2 3 4 5 6 7
Seven by seven, and the seven regions are irregular shapes that hook into one another; not one of them is a rectangle. I once called this format “seven sevens seldom simply seek seven seats”, and the name says enough about how they fit. Follow the thick lines here, not your habit: region 4 runs from the second row down to the sixth and is a single cell wide on four of those five rows. Row, column and region remain the only three rules.
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T and T and U
Size: 7 × 7 Signs: 1 2 3 4 5 6 7
Seven by seven again, but this time I drew the regions myself: two lie across the grid as a T, one as a U, and the four others close the gaps in the corners. Every region holds seven cells, as it must. The two T's are the handiest place to start: their bar takes five of the seven cells of a single row, and their stem hangs two cells below it in the same column. That many cells of one region in one row rules out a great deal at once.
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Windmill sails
Size: 8 × 8 Signs: 1 2 3 4 5 6 7 8
Eight by eight, divided into eight rectangles of four by two. Four of them lie flat and four stand upright, and together they turn like the sails of a windmill around the centre of the grid. Every rectangle carries all eight signs, just as every row and column does. Where a lying and a standing sail meet is usually where you can rule something out fastest.
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Double rectangles
Size: 8 × 8 Signs: 1 2 3 4 5 6 7 8
Eight by eight, and as with the six, two divisions lie on top of one another here. Every sign must appear exactly once in the black-bordered lying rectangle four wide and two high, and exactly once in the coloured standing rectangle two wide and four high. That makes sixteen rectangles on top of the rows and columns: of everything I built, this is the most densely veined grid. Go slowly, because one mistake spreads along two paths at once.
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Classic
Size: 9 × 9 Signs: 1 2 3 4 5 6 7 8 9
The format everyone knows: nine signs, nine blocks of three by three, and beyond that only the rows and the columns. Twenty-seven regions, and no more than that — everything else in the game follows from them. This is the grid I started with myself, and the best place to learn what the hint button does.
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With diagonals
Size: 9 × 9 Signs: 1 2 3 4 5 6 7 8 9
The classic nine, with both diagonals added as regions. Every digit must appear exactly once on each diagonal too — that is the only addition, and it does more than you would expect. The middle cell lies on both diagonals and is therefore the most heavily constrained cell on the board. The diagonals are coloured and hatched, so they stay visible without colour as well.
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Jigsaw pieces
Size: 9 × 9 Signs: 1 2 3 4 5 6 7 8 9
Nine by nine, but I drew the nine blocks myself: they interlock like jigsaw pieces. Exactly one of them is still a real three-by-three square, right in the middle of the grid; the eight others curl around it. Every region holds nine cells, so the rule stays the same — you just have to follow the thick lines now instead of your habit.
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Staircases
Size: 10 × 10 Signs: 1 2 3 4 5 6 7 8 9 0
Ten by ten, with ten regions that run through the grid like staircases: each one shifts sideways by a single cell from row to row. Four stand side by side at the top and four at the bottom; two lie crosswise over two rows in the middle. The signs are the digits 1 to 9 and 0. Do not count on straight blocks here — the thick lines are all you have to go on.
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Staircases and rectangles
Size: 10 × 10 Signs: 1 2 3 4 5 6 7 8 9 0
Ten by ten, and here I mixed staircases and rectangles. In each half of the grid two pairs of staircases interlock, with one straight region between them, two cells wide and five high. That straight region is usually your starting point: it is the only one that keeps neatly to two columns. The rest you read off the thick lines, cell by cell.
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Curls
Size: 10 × 10 Signs: 1 2 3 4 5 6 7 8 9 0
Ten by ten, with eight regions that interlock like spirals: two to a corner, one plain and one filled, turning around one another. In the middle lie two ordinary rectangles, five wide and two high. In this variant the fill is the only difference between two curls that sit side by side; that is why every fill also has a hatching, and why the name of the region is spelled out on every cell. Trace one curl with your finger and you will see at once why I called it that.
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Eleven signs
Size: 11 × 11 Signs: 1 2 3 4 5 6 7 8 9 0 X
Eleven by eleven, and eleven signs: the digits 1 to 9, the 0, and an X as the eleventh. Eleven is a prime number, so it cannot be divided into rectangles; I therefore laid the regions out in bands — three bands of three rows, and one of two at the bottom. Within a band the regions bite into one another along a middle row that juts in and out. Every region holds eleven cells, as it should.
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Twelve signs
Size: 12 × 12 Signs: 1 2 3 4 5 6 7 8 9 A B C
Twelve by twelve, with the digits 1 to 9 and then A, B and C. The blocks are rectangles four wide and three high; twelve of them fit. Beyond that it is simply sudoku, only longer: a hundred and forty-four cells and thirty-six regions. Take your time over it; I do too.
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Sixteen signs
Size: 16 × 16 Signs: 1 2 3 4 5 6 7 8 9 0 A B C D E F
Sixteen by sixteen: two hundred and fifty-six cells, and sixteen signs — 1 to 9, the 0, and then A to F. The blocks are ordinary four-by-four squares, so structurally this is the classic sudoku, blown up. The hard part is not the reasoning but the overview: you have to hold sixteen signs in your head at once instead of nine. On a phone the grid takes the full width of the screen; turning the screen sideways helps.
Still to come
Two grids are listed here without a link. They exist, I made them, but they are not playable yet — and a link to a page that stalls is worse than no link at all.
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Honeycomb, five signs
Not playable yet
Five signs in little hexagons. Perhaps I may no longer call this a SUDOKU? Then call it a honeycomb riddle. The grid is not a square, and the board I built for this site can only draw squares for now. So it is listed here, but you cannot play it yet.
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Honeycomb, nine signs
Not playable yet
Nine signs in little hexagons, with the dropped digits noted in the boxes outside the grid. There is a problem there that I have to sort out myself first: my own pre-filling of those outside boxes turns out to have no solution at all. Checked exhaustively, so it is not a hunch. Until I know how it should be done, I would rather put nothing here.