Introduction to Fractional Sudoku
(Published on 17. April 2025, 04:32 by juggler)
I had the pleasure of hearing Mitchell give a fascinating math talk on Fractional Sudoku a few weeks ago. Everything in his talk made perfect sense to me, except for one remark: that fractional sudoku grids were perhaps not appropriate for making human-solvable puzzles. I’m glad I was able to convince him that he was wrong on that point! Thanks to some heroic software support from Chameleon, we're excited to be able share this starter pack of beginner-level Fractional Sudokus.
Rules (4x4)
- Each puzzle is a 4 × 4 grid of cells, which are arranged in four rows and four columns of four cells each. The cells are divided into cell pieces by gray lines.
- Write a digit from 1–4 in each cell piece.
- Digits may not repeat in a cell.
- In each row, column, and marked 2 × 2 box, the total area of the cell pieces containing the digit 1 must equal the area of a single cell. The same is true for the digits 2, 3, and 4.
- When cell pieces in the same cell have equal size, you may enter their digits in either order.
1. Close Quarters
2. Mitosis
3. Funky Town
Rules (6x6)
- Each puzzle is a 6 × 6 grid of cells, which are arranged in six rows and six columns of six cells each. The cells are divided into cell pieces by gray lines.
- Write a digit from 1–6 in each cell piece.
- Digits may not repeat in a cell.
- In each row, column, and marked 2 × 3 box, the total area of the cell pieces containing the digit 1 must equal the area of a single cell. The same is true for the digits 2, 3, 4, 5, and 6.
- When cell pieces in the same cell have equal size, you may enter their digits in either order.
5. Fractionally Harder
Solution code: Row 4 of the last puzzle (for fractional cells, enter digits in increasing order)
Comments
on 24. June 2025, 19:15 by wisty
Really cool concept! The 6x6 grid's roping pattern allows for some neat logic with how single cells interact with fractional ones. I wonder what kinds of irregular grids could exist with this ruleset. Two years ago I would have tried to make a SET puzzle lol
on 23. April 2025, 22:12 by dzamie
These were so cool! Though I shudder to imagine what monstrosities this could lead to if people manage to add additional rules to it...
on 22. April 2025, 22:06 by juggler
(CtC video link)
on 22. April 2025, 16:53 by jaeger_puzzles
That was so much fun! I really hope we see more puzzles in this style, it was truly a delight to figure it out!
on 21. April 2025, 06:06 by jinkela114514
Will there be a 9x9 version?
on 18. April 2025, 20:12 by topoi
What wonderful fun!!!
The third puzzle took me forever, because one of the fractional cells lined up with a crack on my phone screen. It looked like a whole cell! lol
on 17. April 2025, 21:25 by Joanie
So wonderful! I am excited to see more puzzles in this style :)
on 17. April 2025, 19:35 by SZCrow
very simple but very new and fun. I can see a lot of potential in this. Looking forward to the real challenge.
on 17. April 2025, 18:57 by Exigus
Thanks for the introduction, very nice, slightly different mind-bending required than usual.
on 17. April 2025, 18:23 by wuc
Very refreshing type of puzzle. Especially the ladt one was huge fun.
on 17. April 2025, 17:58 by Voidslime
I’m so happy to see and enjoy you actualizing this! Opposite to timo, i struggled with 1-4 but then it all clicked and 5 was a breeze.
I hope there’sa way to make a fractional coloring puzzle. I tried to play 3 and 4 here as coloring puzzles but it was unhelpful.
I can’t wait to see more puzzles and unique interactions in this ruleset. I might try setting some myself!
Regardless, really cool and fun experimental puzzle set!
on 17. April 2025, 17:24 by aqjhs
hooray for puzzleTV!
on 17. April 2025, 14:22 by josebastian8
What a strange yet amazing type of puzzle! I'd love to see them merging with some other variants, like killer cages.
on 17. April 2025, 10:49 by giladooshlon
Such an interesting concept and a lovely introduction. Looking forward to some variants on this thing.
Kudos to Chameleon on the software!
on 17. April 2025, 05:15 by timotab
The first four I managed to do fairly quickly, but the fifth one almost broke my brain. Great puzzles!
on 17. April 2025, 04:36 by MattYDdraig
An excellent collection and introduction. It will be interesting to see how well this expands to 9x9, and possibly smaller fractions.
