Sudoku Sensei: Learn & Master

I made this because I wanted hints that tell me what I missed. Tap Hint and it highlights the cells for the easiest next step and names the technique. Tap Why? for the reasoning in a sentence or two, then Apply to make the move. With mistake checking on, a wrong digit gets a one-line reason, like "Row 4 already has a 6." If you ask for a hint while a wrong digit is still on the board, the hint points that out first. TECHNIQUES There are ten: naked and hidden singles, naked and hidden pairs, pointing pairs and triples, box-line reduction, naked triples, X-wing, XY-wing and swordfish. Each one gets its own page with an example board and a short lesson. A ring on the page fills as you find the technique without a hint, and after five it's full. Pro adds practice drills for each technique. Every drill is a position where you need that technique to make the next move. iPhone Duo Open the…