Logic Masters Deutschland e.V.

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My Variant Sudoku 101 series introduces common variant sudoku rules, frequently using dynamic fog to help point the solver where to look next. The target audience is those who are comfortable with classic sudoku, but new to variant sudoku. In other words, you are expected to be able to identify things like (but not limited to) pairs and triples in rows/columns/boxes and know how to take advantage of them. I welcome everyone to try this series regardless, just be warned you may have a harder time if you're new to sudoku in general.

Rules:

• Normal sudoku rules apply. Place the digits 1-9 in each row, column, and 3x3 box without repetition.
• Dynamic Fog: The grid is partially covered in grey fog. Placing correct digits will clear the fog, at minimum under that cell and sometimes in other parts of the grid. No guessing is required.
• German Whispers: Adjacent digits on a green line must have a difference of at least 5.
• Renban: Digits placed on purple lines must be a non-repeating set of consecutive digits in any order. For example, a 3-cell line could contain the digits 456, arranged as 456, 564, 465, etc.

Solve on SudokuPad here!
Visual impairment friendly version: here. This version has text abbreviations specifying which clue is which rule. RB for renban, GW for German whisper.

To increase accessibility to my puzzles, I include hints in my puzzle posts (see below). I also post solution videos on my Patreon and YouTube channel. Puzzles released prior to February 2026, as well as my snackdoku and variant sudoku 101 series will continue to get public solution videos on YouTube, while others will be Patreon-exclusive.

Hint 1: The 7-cell renban in row 1 is powerful like the previous puzzle, but it requires more thinking to work out. Note that the German whisper line extends to the corners of the renban, and that whatever the low/high pattern of the whisper is, the ends will be opposite polarity to each other. This is enough to place a 19 pair into the corners, because that is the only set of 2 digits you can place outside the renban that are opposite polarity.
Hint 2: R2C5 can be determined to be low or high due to the pattern of renbans in box 8, and knowing that it can't be 4 or 6 due to whisper logic.
Hint 3: You can now fill in the other renbans in box 8. This is critical for proving the low/high pattern of the newly revealed German whisper in box 4 which dips into box 5.
Hint 4: Box 7's pattern is difficult to work out. Note that the renban can't be 123, 456, or 789 else it'd break the box 8 renbans. That, along with the given 6 in the box, heavily limits what set of digits could be on the box 7 renban. It must be either 234 or 345, either way there's a 3 and a 4 on it. After, apply a similar trick to the box 9 center renban, which can't have a 5 or a 9 on it without breaking box 8.
Hint 5: The column 9 renban must have both a 5 and a 6 on it, using a similar strategy to before. 9 now only has one place it can go in the column, and you get a 78 pair in the column.