One grid, many twists
Every sudoku variant starts from the same idea: fill a grid so that each digit appears exactly once in every row, column, and region. What the variants change is the shape of the grid, the shape of the regions, or the extra constraints laid over the top. None of them throw away the classic solving habits — naked singles, hidden singles, pointing pairs, and the rest all still apply. They simply give you an additional rule to lean on, which usually means an additional way to make progress when the standard logic stalls. This guide walks through the six non-classic, non-killer variants in Sudoku by WizusLabs, one at a time.
Mini (6×6)
Mini sudoku shrinks the board to six cells by six, divided into six rectangular boxes of two rows by three columns. You place the digits 1 to 6 instead of 1 to 9, and the three rules are otherwise identical: no repeat in any row, column, or box. The smaller grid means far fewer candidates per cell and a much shorter solve, which makes Mini the friendliest place to learn the mechanics or to fit a full puzzle into a couple of minutes.
Tip. Because each box is only six cells, hidden singles jump out quickly — scan each box for a digit that can go in just one of its cells before you reach for anything fancier. On a six-grid that alone often carries you most of the way to the finish.
Irregular (Jigsaw)
Irregular sudoku, also called Jigsaw, keeps the nine-by-nine grid and the digits 1 to 9 but throws away the tidy three-by-three boxes. In their place are nine irregularly shaped regions that interlock like puzzle pieces — each still nine cells, each still required to hold every digit once. The row and column rules are unchanged; only the third region changes shape.
Tip. The bent regions create constraints classic sudoku never offers. When a region snakes across several rows or columns, a digit placed in it can eliminate candidates in surprising places, so trace each region's outline carefully and watch where it overlaps a nearly-full row or column — that is where the extra deductions hide.
X-Sudoku
X-Sudoku adds two rules to the classic board: the two main diagonals must each also contain the digits 1 to 9 exactly once. The name comes from the X those diagonals trace across the grid. Everything else is standard nine-by-nine sudoku, so the diagonals are pure bonus constraints layered on top of the usual three.
Tip. Treat each diagonal as a fourth kind of unit and pencil it into your scanning routine. The centre cell sits on both diagonals at once, so it is unusually constrained — pin it down early and the two diagonals often unravel from there.
Windoku
Windoku, sometimes called Hyper sudoku, keeps the nine-by-nine grid and its three classic rules and adds four extra shaded three-by-three regions, offset from the standard boxes toward the centre of the board. Each of those four "windows" must also contain the digits 1 to 9 exactly once. The shaded regions overlap the ordinary boxes, so many cells belong to two region constraints at once.
Tip. The overlap is the whole point. A cell that sits in both a standard box and a shaded window is constrained twice over, so it will usually resolve before its neighbours. Work the shaded regions and their overlaps first, and the extra windows do a lot of the elimination for you.
Even-Odd
Even-Odd sudoku plays on the classic grid with the classic three rules, but some cells are marked to tell you the parity of the digit they hold — a shaded or circled cell must contain an even digit (2, 4, 6, 8), while the rest hold odd digits (1, 3, 5, 7, 9), or the marking scheme is reversed as the puzzle specifies. The parity marks act like partial givens, narrowing each marked cell to just four or five candidates before you place a single number.
Tip. Start by mentally halving the candidate list in every marked cell — an even-marked cell can only be 2, 4, 6, or 8, so cross the odds off immediately. That head start often turns an otherwise ordinary puzzle into a chain of quick eliminations.
12×12
The 12×12 variant scales the whole idea up. The grid is twelve cells by twelve, divided into twelve rectangular boxes of three rows by four columns, and you place twelve symbols — the digits 1 to 9 plus three more, often shown as 10, 11, and 12 or as letters. Every row, column, and box must contain all twelve symbols exactly once. It is the same game with more room and more bookkeeping.
Tip. With twelve candidates per cell, disciplined pencil-marking stops being optional — note candidates as you go and prune them steadily. Because the boxes are three by four rather than square, pointing pairs and box-line reductions fire along the longer edge more often, so watch those four-wide rows inside each box.
The habits that carry across
Whichever variant you pick, the foundation is the same. Learn to spot naked and hidden singles, get comfortable with pointing pairs and box-line reductions, and keep your pencil marks honest. Every variant above is just that foundation plus one clearly stated extra rule, so the fastest way to enjoy them is to be solid on the classic game first. If any of the terms here are unfamiliar, the sudoku glossary defines them in plain language.
Where to play them all
Sudoku by WizusLabs ships all of these variants alongside classic and killer, across six difficulties from Easy to Grandmaster. Every puzzle is generated on device, works offline with progress saved locally, and has exactly one solution — so no matter which variant you are exploring, the logic always resolves without guessing, and candidate notes are built in to help you track it.
Keep reading: classic vs killer sudoku · killer sudoku rules and strategy · all guides