Dutch Flat Mates: Binary Sum Arrows
(Eingestellt am 5. November 2025, 08:00 Uhr von damo_89)
It is once again a great pleasure to feature in the long-running Dutch Flat Mates series by Flinty. This week the paired constraint is Binary Sum Arrows. If you'd like other puzzles featuring this constraint, I can recommend the following by its creators:
Rules:
- Normal sudoku rules apply: Place the digits 1 to 9 once each in every row, column, and 3x3 box
- Dutch Flats: Every 5 in the grid must have a 1 directly above it or a 9 directly below it. It may have both, but it doesn't need both
- Binary Sum Arrows: Arrows contain "binary sums". Each cell along the arrow is a bit, starting with the most significant bit and going to the least significant. If a cells contents are odd, that puts a 1 in that bit, and if a cells contents are even, that puts a zero in that bit. The digits in the bulb of the arrow are that sum expressed as a one or two-digit decimal number (read from left-to-right)
- (For example, a five cell arrow would have a 16's bit, an 8's bit, a 4's bit, a 2's bit, and a 1's bit. Cells with odd odd even even odd along that arrow would then give a binary sum of 16 + 8 + 0 + 0 + 1 = 25)
Play on Sudokupad
Download full solution guide (PDF)
Previous Dutch Flat Mate Puzzles
This has been a weekly series since '18 Oct 23'. Here is a spreadsheet link for all the previous puzzles in the series, which also has a few teasers for upcoming constraints/guest setters in the series (subject to change).
This alternative link offers a limited LMD search for Dutch Flat Mates.
Lösungscode: Row 5
Zuletzt geändert -
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Kommentare
am 7. November 2025, 23:34 Uhr von VitP
i got about halfway through, and ran into a brick wall.
did i forget a rule?.
lol
am 7. November 2025, 01:21 Uhr von Aronana
Very Nice! Liked the touch of adding in the digits to make the binary easier to read.
am 6. November 2025, 14:09 Uhr von Flinty
You've done a wonderful job with this, it's an excellent puzzle. x
am 6. November 2025, 06:40 Uhr von gaihou
It gets much easier to solve by parity,love this Sudoku
Zuletzt geändert am 5. November 2025, 15:29 Uhram 5. November 2025, 08:44 Uhr von Mozart40
Sounds like a great constrain to me. But I've no clue how to approach this.
/Edit: Okay two numbers found. Looks like a way to go.
/Edit2: After finding a way to think about it, it was a pleasure. Thx for sharing.