Play on SudokuPad
Normal sudoku rules apply.
Draw a line between circles of the same color. Lines may not move diagonally, can't cross themselves or other lines, and cells can't have more than one line in them. Depending on the color, the lines are one of the following types:
Purple: Renban - Contains a set of non-repeating, consecutive digits in any order.
Blue: Region Sum - Digits on the line have an equal sum N within each box it passes through. If a line passes through the same box more than once, each individual segment sums to N separately.
Grey: Palindrome - Digits read the same from both directions.
Green: Modular - Every set of three sequential digits along this line must contain a complete set of residues modulo 3, i.e. one digit from {1,4,7}, one from {2,5,8}, and one from {3,6,9}.
Cells separated by a black dot must both have a line in them, though not necessarily the same line. Their digits have a 1/2 ratio.
Enabling the pen tool in the settings is recommended.