Logic Masters Deutschland e.V.

Standard Sudoku: Put the digits 1-9 once in each row, column and box.
Nabner lines (golden): A nabner line does not contain consecutive digits.
Entropic lines (peach): Any set of three sequential cells along an entropic line must contain a low (123), a middle (456), and a high digit (789).
Region sum lines (blue): Box borders divide region sum lines into segments with the same sum.
Play in Sudokupad.