The 6 elements in each group of this type of puzzle are: 1, 2, 3, 4, 5, and 6.

Every group in the puzzle must contain exactly this set of elements.

There are 28,200,960 possible unique solutions for this type of puzzle.

In a Sudoku-Junior puzzle, each row is a group numbered as shown in the figure above.

In a Sudoku-Junior puzzle, each column is a group numbered as shown in the figure above.

In a Sudoku-Junior puzzle, each 3x2 rectangle is a group numbered as shown in the figure above.