Normal Sudoku rules apply. Place the digits 1-9 once each in every row, column, and 3x3 box.
Two digits separated by a chess knight’s move cannot contain the same digit.
Draw a non-branching, orthogonally-connected, one-cell-wide loop that visits every 3x3 box at least once. The loop may not touch itself orthogonally but may touch itself diagonally. The large circle in r1c1 means that that cell is part of the loop.
Restricted Tunnels: Between some cells, there are large, colored dots with different colored tunnels going through them. If the loop passes through a tunnel, the tunnel restriction is used for the separated cells. If the loop does not pass through the tunnel, the large dot’s restriction is used for the separated cells. It is not permissible for both the tunnel’s restriction and the large dot’s restriction to be true simultaneously.
Tunnel and dot color restrictions:
-Black: separated cells have digits in a 2:1 ratio.
-Pink: separated cells have consecutive digits.
-Green: separated cells have digits with a difference of at least five.
-Orange: separated cells have digits with a difference of at least four.
-Gray: separated digits sum to five.
-Blue: separated digits sum to ten.
To Play:
SudokuPad