Sudoka 4+

The essential application for any Sudoku enthusiast, beginner or experienced, without advertising or in-app purchases.

Resources
• integrated grid generators for three levels of solving difficulty (press one of the three loading buttons, red, orange or green on the upper banner)
• grid level indicator (round patch of the upper band), whether provided by the app or entered on the keyboard, based on the following classification:
- 1) grids solved without indicating the candidates (generated by pressing a green button and identifiable by a green dot)
- 2) grids requiring the removal of candidates registered in the same area (generated by pressing an orange button and identifiable by a dot of the same color)
- 3) grids requiring, in order to remove candidates, to be based on candidates registered everywhere on this one (red dot and red button)
- 4) grids requiring to force candidates to progress (not generated by this application but identifiable by a black dot)
Tools
• possibility of filling in the candidates in the cells if necessary (press the "pen" icon, present at the bottom left of the screen, before entering the keyboard)
• using your finger as a marker to highlight an area or a cell
• possibility of ignoring the steps requiring the use of a technique considered to be known (press the “fast forward” button)
• automatic writing of candidates in cells if desired (press on the “cell(s)” icon in the upper banner)
• possible recovery of the contents of a cell if error (press the “back” button)
Training
• documented solutions available with color highlighting of grid areas or cells (press the text box at the bottom of the screen for a "step by step" explanation, or press the "advance" button, located at the bottom right, for the solution to the current step)
• backtracking possible on each step after viewing a solution or displaying help so that the step in question can be taken alone (press the “back” button at the bottom left of the screen)
• presentation of the nineteen common methods used to solve a sudoku with many examples available for each method (press the “teacher hat” button located in the upper banner then press the desired method in the displayed list)
Getting started
• quick training button to use the application (press the "?" icon in the upper banner)
• detailed information panel for all features (press the "i" button on the button bar)
Help
• drop-down message for help finding a solution and using the application if desired (press the “teacher” icon located at the bottom right of the screen)
• indications for progress, without providing a solution, if you feel blocked (press on the text box at the bottom of the screen)
• solution at each resolution step if desired
Ergonomics
• position of the buttons on the sides for iPad and at the bottom of the screen for iPhone
• full functionality on a single screen page
• opening the application directly on the grid
Comfort
• modification of the lighting if necessary, "dark mode" available (press on the "moon" or "sun" icon in the upper banner)
• activation or deactivation of sounds if desired (press the “speaker” icon in the upper banner)
Mobile use
• no network connection required
• automatic grid saving