Bubble Sudoku

Bubble Sudoku is made by Pop Logic Studios LLC, a one-person studio, and came out in 2026. The rules are the ones you know: every row, column and 3x3 block holds each of the nine colours once. The only change is that coloured bubbles take the place of the digits, which the site uses to make the point that sudoku is logic, not maths.

The daily board is the same for every player, with a countdown to the next one. Its level changes through the week, gentler early on and hardest at the weekend, with each month holding the same mix of levels. In the app the dailies sit on a calendar, and finishing a whole month earns that month's hand-drawn trophy. Outside the daily you can play boards at four levels, Easy, Medium, Hard and Expert, each graded by the techniques it needs: Easy uses only obvious singles, Expert can call for X Wing and Swordfish. No board needs a guess.

What sets it apart is how it helps. A hint names the technique that solves a cell and walks through it on your board, and fifteen lessons run from Full House up to Swordfish. Notes are small coloured dots, and in the app you can hide the timer or turn off mistake checking so a wrong bubble does not cost a life.

It suits players who find rows of digits dull, newcomers who want to learn sudoku technique properly, and anyone after a calm daily grid.

The browser version shows no ads. The iPhone and Android apps are free with ads, and a one-time Bubble Sudoku Plus purchase removes them and makes hints unlimited.