Normal sudoku rules apply. Circles represent one end of a "Between Line". Circle digits give the length of the rest of the line including line cells and the other endpoint (eg 3 = 2 line cells + the other endpoint cell). Other endpoints are not circled digits. Line digits must have a value between the two endpoint digits. Lines may only move orthogonally, cannot cross or share endpoints. All Between Lines have at least one line cell. Endpoints of the same Between Line may not be in orthogonally adjacent cells.