This is an example of a completed Renban Sudoku grid.

All the normal rules of Sudoku apply, but the grid also contains Renban lines. The cells on Renban lines must contain distinct (no repeating) consecutive values. The values can be in any order - they don't need to be consecutive along the line.

If a Renban line covers 4 cells, these

This is another example of a completed Renban Sudoku grid.

You will notice that the values on the Renban line are sometimes in order, but not always. As long as they are consecutive with no repeats, the placing is valid.