Top Right Boi
(Published on 21. June 2025, 12:00 by PhoenixAki)
- 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.
- Top Right Boi: For every clue in the grid, the rightmost cell of the top row of that clue must have its largest digit. For example, a 2x2 cage requires its largest digit in the top right cell. Similarly, a black dot needs its larger digit on the top or right (depending on orientation).
- Regional Constraints: No digit may appear more than once on each clue type. For example, if a cage contains a 2, no other cage can contain 2's.
- Renban: Digits placed on purple lines must be a non-repeating set of consecutive digits in any order.
- Killer Cages: Digits in dotted-line cages must sum to the number in the top left corner of the cage. For clarity, in this puzzle, this means the leftmost cell of the top row. Digits may not repeat within a cage.
- Ratio Pairs: Digits separated by a black dot must have one digit be double the other (a 2:1 ratio).
- German Whispers: Adjacent digits on a green line must have a difference of at least 5.
- Arrows: Digits on an arrow must sum to the digit placed in that arrow's circle. Digits may repeat on an arrow if allowed by other rules.
- Maximum: Purple cells must be greater than all orthogonally adjacent cells. Only the maximum cells themselves interact with other rules.
Visual impairment friendly version: here. This version has text abbreviations specifying which clue is which rule. RB for renban, GW for German whisper, AR for arrow, M for maximum cells.
To increase accessibility to my puzzles, I include hints in my LMD posts and also post solution videos on my YouTube channel. I hope these help you solve the puzzles if you are struggling :)
Hint 1: Always be thinking about both Top Right Boi and Regional Constraint. The renban lines are an example of a clue that requires thinking about both rules. Regional constraint means one will be 123, another will be 456, and another will be 789. Then apply Top Right Boi :)
Hint 2: The shape of the 19 cage in box 8 is deducible through the wording of the killer cage rule. Then, think about how you could have both 19 cages coexist without breaking regional constraint.
Hint 3: You should be able to get the 2 black dots whittled down to 4 digits total. Then, look for a cell that sees all 4 of the dotted cells.
Hint 4: The arrows are specially affected by Top Right Boi. Think about where the circle must be in relation to the arrow itself.
Solution code: Row 9 from left to right (9 digits)
Comments
on 12. January 2026, 11:24 by PhoenixAki
Added hints after learning recently how to do that in HTML. Wish I knew this last week when I went over all my posts...oh well.
on 5. January 2026, 19:50 by PhoenixAki
Updated post as part of an effort to improve consistency of rule phrasing and post layout across all my puzzles. I also included a link to a second version of the puzzle that's more accessible to solvers with visual impairments such as colorblindness.
on 18. December 2025, 20:38 by PhoenixAki
Another clarification update. Improved upon the wording changes I made a few weeks ago to clear up some remaining ambiguities. Also changed maximum cells to be colored purple to visually distinguish them from fogged cells (previously, once revealed, they'd still be grey).
on 12. December 2025, 06:04 by marajade
Fog and regional constraints are two of my favorite things, and I loved how the top right rule combined with everything! Such a fun experience to solve.
on 27. November 2025, 12:37 by alta1r
Didn't think i'd get to solve that in just over 20 minutes ! The final fog reveal was unexpected, but really pleasant !
on 18. November 2025, 03:17 by PhoenixAki
Updated the language of the rules to clarify doubts on how maximum cells interact with Top Right Boi + Regional Constraints. A few months late but better late than never lol. Also updated fog so that all remaining fog clears once all clue-related deductions are done (will be implementing this into my other puzzles as well). Happy solving!
on 10. September 2025, 14:26 by eap314
Kept forgetting the top right rule and resorting to sudoku, then suddenly remembering and making a lot of progress
on 27. July 2025, 21:06 by MattJones
I loved this! Really interesting break in, took me a while to bludgeon it in submission! Brilliant.
on 3. July 2025, 13:52 by Atticus837
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on 1. July 2025, 14:18 by SweJo
Very nice!
on 1. July 2025, 08:08 by PancakePie
Beautiful!
on 23. June 2025, 16:15 by dkfan9
Nice puzzle. I was uncertain on the max cell relation to the other rules, but determined it could only work if the cells around it don't count as part of the constraint, only the max cell itself. I have no qualms with that, it's perfectly logical, but not initially intuitive for myself.
on 22. June 2025, 13:11 by TopRightBoi
This is the best puzzle I have ever solved.
on 22. June 2025, 05:01 by jinkela114514
How does the regional constraint work on max cells?
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PhoenixAki: No different than the others - if you were to work out one of the maximums is a 5, then no other maximum can be a 5.
on 21. June 2025, 23:53 by ViKingPrime
Love the interaction between all of these clues.
on 21. June 2025, 14:58 by sujoyku
Thank you for this nice puzzle, PhoenixAki! Go top right boi, go!
on 21. June 2025, 12:57 by illegel
I really stuggled at the beginning until I remember that the total of killer cage should be in the upper left. Really interesting puzzle！
on 21. June 2025, 12:08 by SudokuFan
Top Right Boi
