Normal sudoku rules apply. Adjacent digits along a GW (“German Whisper”) line must differ by at least five. Any set of three adjacent cells along an Ent (Entropy) line must contain a low digit (123), a middle digit (456), and a high digit (789). If two digits are separated by a black dot, one is double the other. Not all black dots are necessarily given. Digits separated by a white dot are consecutive. Not all white dots are necessarily given. Digits along grey lines (“Ten Lines”) must be broken into one or more contiguous groups of cells that sum to ten. Such groups cannot overlap. Digits may repeat within such sums if allowed by other rules. Eg 513173 is a valid fill for a length 6 line, because it can be broken into 5131 and 73, each of which sum to 10. Adjacent digits along a DW (“Dutch Whisper”) line must differ by at least four. Digits along a PR line alternate odd/even. No two digits along a Nab (“Nabner”) line can be consecutive, regardless of their position on the line.