If you already enjoy standard Sudoku, trying a variant can feel like discovering a whole new puzzle. The same logic still applies, but each variant adds a rule that changes how you think. Diagonal Sudoku, Jigsaw Sudoku and Samurai Sudoku are three of the most popular twists. They are easy to learn and offer a satisfying challenge without needing to guess. Here is what makes each one different and why you should give them a try.

What Makes These Variants Different

Standard Sudoku uses a 9x9 grid of 81 cells divided into nine 3x3 boxes. Each row, column and box must contain the digits 1 to 9 exactly once. A well-made puzzle has exactly one solution and can be solved by logic alone, without guessing. The minimum number of starting clues for a unique solution is 17, proven by computer search in 2012. The puzzle was popularised in Japan under the name Sudoku and spread worldwide in 2005 after newspapers began printing it.

Variants change one or more of those rules. Diagonal Sudoku adds two new regions. Jigsaw Sudoku replaces the 3x3 boxes with irregular shapes. Samurai Sudoku overlaps five grids at once. Each variant makes you think in new ways while keeping the core logic you already know.

Diagonal Sudoku

Diagonal Sudoku keeps the standard rows, columns and 3x3 boxes, but also requires that the digits 1 to 9 appear exactly once on both main diagonals. The two diagonals run from the top-left corner to the bottom-right corner, and from the top-right corner to the bottom-left corner. This adds only two extra regions, but they often restrict possibilities enough to change your solving strategy.

How It Changes Solving

In a standard puzzle, you can place a number based on what is missing in a row, column or box. In Diagonal Sudoku, you also have to check the two diagonals. A candidate that looks good for a row might be blocked because it already appears on a diagonal. This forces you to look across the entire grid more carefully. Many solvers find that the extra restriction actually makes some puzzles easier, because the diagonals eliminate many possibilities early on.

To get started, mark the two diagonal cells clearly. When you pencil in candidates, always check whether a number already appears on the same diagonal. The same logic rules apply: each diagonal must contain all digits from 1 to 9 exactly once.

Jigsaw Sudoku

Jigsaw Sudoku removes the familiar 3x3 boxes. Instead, the grid is divided into nine irregularly shaped regions, often called jigsaw pieces or cages. Each region must contain the digits 1 to 9 exactly once. The rows and columns keep the same rule. The irregular shapes make it harder to see where a number can go, because the shapes are not uniform.

Tips for Solving Jigsaw Puzzles

  • Focus on small regions first. Look for jigsaw pieces that have only a few cells left. Those are easier to fill.
  • Use the shape to your advantage. Irregular pieces often stretch across multiple rows and columns. A number that fits in one part of the shape may be blocked in another part.
  • Keep track of rows and columns. The row and column rules still apply. If a number is forced into a certain row, it can eliminate candidates in the jigsaw piece.

Jigsaw puzzles can feel more open than standard ones, because the shapes do not align with the rows and columns. That also means you cannot rely on the usual box patterns. It is a good variant for solvers who want a fresh visual challenge.

Samurai Sudoku

Samurai Sudoku is a large puzzle made of five overlapping standard 9x9 grids. The five grids are arranged in a cross shape: one in the centre, one above, one below, one to the left and one to the right. The overlapping areas are shared between two grids. Each individual grid must obey the standard Sudoku rules. The overlap means that a digit you place in the shared region affects both grids at once.

How the Overlap Works

The centre grid shares a 3x3 box with each of the four outer grids. When you solve the centre grid, those shared boxes also become part of the outer grids. This creates a tight interdependence. A mistake in one grid can break two or more others. Many solvers work on the outer grids first, leaving the centre grid for last. Others start with the centre because it connects to everything. Try both approaches to see what suits you.

Samurai puzzles take longer to solve, often thirty minutes or more. They are a good choice when you want a long session.

Where to Find These Variants

If you want to try any of these variants, you can find them at a site that offers a wide selection. For example, you can play Sudoku online at sudoku.by, which provides 30+ variants including Diagonal, Jigsaw, Samurai, Killer, Hyper/Windoku, Thermo, Arrow, Sandwich, Kropki and Mini 4x4. The site also includes technique guides, daily challenges and six difficulty levels so you can start at a comfortable pace. Whether you are new to variants or a seasoned solver, having access to many types in one place makes it easy to explore.

Which Variant Should You Try First

If you are comfortable with standard Sudoku, start with Diagonal Sudoku. It adds only two extra regions and feels like a small twist. Jigsaw Sudoku is a good next step if you want a visual change without the complexity of multiple grids. Samurai Sudoku is best saved for when you want a long, immersive puzzle. All three variants can be solved with logic alone, just like the original. Choose the one that matches the time and mental energy you have available.