Interactive letter Sudoku online game for kids. This logic game has a single square in which to check that the letters are different in both rows and columns. To change the letters, use the SWAP method, choose a letter and its new place, so that they swap positions. You can choose to play a 4x4 letter sudoku, a 5x5 letter sudoku or a 5x5 sudoku. A letter sudoku or Wordoku game to play for free online, especially geared for children learning Sudoku and its rules.