Sudoku Vault is a logic-based puzzle game featuring 4x4, 6x6, and 9x9 boards — each with four difficulty levels: Basic, Normal, Hard, and Expert. Whether you're a beginner or an expert, every grid offers a fresh challenge for your mind. Use smart NOTES to keep track of possibilities, and when you want to check your progress, tap the CHECK button — it will remove incorrect inputs and lock the correct ones, helping you stay focused on the solution. Sudoku, Sudoku game, logic puzzle, 4x4 Sudoku, 6x6 Sudoku, 9x9 Sudoku, puzzle game, brain game, mental exercise, challenging, beginner Sudoku, expert Sudoku, kids Sudoku, cognitive skills, thinking, logic, number puzzles, free puzzle game