agrozoo.net - Sudoku, Samurai soduku - online logical game
Soduku
- Start with 4x4 soduku to get the idea.
- Basic thing is that in each row/column/inner square(marked red), each number can appear only once.
- If yellow message appears, it means that you broken rules in that part of grid.
- Click on blue numbers to get another variation of game.
- Detailed explanation: Wikipedia