Sudoku — see what fits

There are no full-screen ads in this game. Not between puzzles, not on launch, not ever. Ads appear as a small banner at the bottom and nothing else. YOU CAN SEE WHAT FITS BEFORE YOU PRESS Tap a square and the digit buttons appear. Digits that cannot go in that square are pale and struck through. Entering a wrong digit by accident is simply not possible. A PALE DIGIT IS STILL A BUTTON Press one and the square that is in the way lights up on the board. Not "7 does not go here" but "there is already a 7 *there*". It points at the reason, so there is nothing to read and remember. IT TELLS YOU THE MOMENT THE PUZZLE IS LOST Some digits break no rule and still leave the board unsolvable. The worst part of sudoku is noticing the contradiction twenty moves later and clearing the lot. You are told as the digit goes in. Take it back and carry on. THERE IS NO NOTES MODE TO FORGET The digit buttons open for one square and close again, so there is no lasting mode you can leave switched on by mistake. Tapping a square does not write anything either, so a stray tap cannot wipe a digit you had right. IF YOU WANT NONE OF THAT Turn Help off in the settings and the board behaves like paper. - Write any digit anywhere - Clashes are shown in red, not prevented - Nothing warns you that the puzzle is lost - Notes are available Only direct clashes along a row, a column or a box are ever greyed out. Hidden singles, locked candidates and naked pairs are all still yours to find. The difficulty is not reduced. 54 PUZZLES, 4x4 UP TO 9x9 It does not start at 9x9. Eight 4x4 boards, twelve 6x6, then fourteen gentle 9x9, twelve regular and eight harder. Every board has been machine-verified to have exactly one solution. There is no guessing. IF COLOURS ARE HARD TO TELL APART The board and button colours were chosen by measurement, checked through simulations of protanopia, deuteranopia and tritanopia. Colour is never the only signal. A digit that cannot fit is struck through, and the square in the way is outlined. Text contrast meets the stricter of the international grades, the one intended for readers with reduced acuity. Works with no internet connection. No account, no sign-up, no personal data. LINKS Terms of Service https://b19.co.jp/terms-of-service/ Privacy Policy https://b19.co.jp/privacy-policy/