Question 1

Why do most sudoku apps have a 3-mistake limit — and does this one?

Accepted Answer

Many popular sudoku apps end your game after three mistakes so you'll watch an ad or buy "lives" to continue. Sudoku by Joseph never does this: there are no lives, no coins and no energy bars. Make as many mistakes as you need — it's your puzzle.

Question 2

Does Sudoku by Joseph work offline?

Accepted Answer

Yes. Puzzles are generated on your device, so every variant works in airplane mode — on the subway, on a flight, anywhere.

Question 3

Which variants are free, and what does premium cost?

Accepted Answer

Classic, Jigsaw and Killer sudoku are included in the free, ad-supported download. Premium unlocks all 12 variants and removes ads, with a 7-day free trial. Pricing varies by country — check the App Store for your local price.

Question 4

What is the 45 rule in Killer Sudoku?

Accepted Answer

Every row, column and 3×3 box must sum to 45 (1+2+…+9). Subtract the sums of cages fully inside a region from 45, and the remainder tells you what the leftover cells must add up to. It's the single most useful Killer technique.

Question 5

Is Killer Sudoku harder than regular sudoku?

Accepted Answer

Not necessarily. Killer adds cage arithmetic on top of normal sudoku logic, but an easy Killer is gentler than a hard Classic. Difficulty depends on the techniques required, not the variant.

Question 6

What's the difference between Jigsaw and regular sudoku?

Accepted Answer

Jigsaw sudoku (also called irregular or squiggly sudoku) replaces the 3×3 boxes with irregularly shaped regions. Rows and columns work as usual; the regions are the twist.

Question 7

How many grids does Samurai Sudoku have?

Accepted Answer

Five overlapping 9×9 grids — four corner grids each share a 3×3 box with the one in the center, and the shared boxes must be valid in both grids at once.

Question 8

Does fewer clues mean a harder sudoku?

Accepted Answer

No — that's a common myth. Difficulty comes from which solving techniques a puzzle requires, not how many givens it has. A 24-clue puzzle can be easy and a 30-clue puzzle can be brutal.

Question 9

Is sudoku a math game?

Accepted Answer

Classic sudoku involves no arithmetic at all — the digits are just nine distinct symbols, and solving is pure logic. Killer Sudoku is the exception: its cages add real addition to the mix.

Question 10

Should I guess in sudoku?

Accepted Answer

A properly constructed sudoku never requires guessing — there is always a logical next step. When you're stuck, pencil marks (notes) usually reveal it.

Question 11

How much does it cost to remove ads in sudoku apps?

Accepted Answer

Some popular sudoku apps charge a monthly fee just to remove ads — and nothing else changes. Here, one premium subscription removes ads and unlocks all 12 variants. Pricing varies by country; check the App Store.

Question 12

What is 16×16 sudoku called?

Accepted Answer

It goes by Super Sudoku or Hexadoku. The grid is 16×16 with 4×4 boxes, so each row, column and box holds sixteen distinct symbols instead of nine.

The sudoku app with 12 variants — no lives, no coins, no nonsense.

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12 sudoku variants

Sudoku guides

Sudoku apps without lives or mistake limits

What sudoku difficulty levels actually mean

How to play Killer Sudoku

Killer Sudoku cage combinations

Every sudoku variant explained

How to play Samurai Sudoku

Frequently asked questions

Pricing

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