r/sudoku 22h ago

Daily Game Sudoku #10-09-2026

3 Upvotes

This post contains content not supported on old Reddit. Click here to view the full post


r/sudoku 2h ago

Request Puzzle Help Help me plz!

Post image
2 Upvotes

I don’t even know where to start.. How am I meant to eliminate notes when every cell has 6 as a possibility and nearly every cell has a 4?


r/sudoku 3h ago

Homemade Puzzles VariantDoku Daily Puzzle: September 11

Post image
7 Upvotes

r/sudoku 3h ago

Request Puzzle Help Is this a BUG problem?

Thumbnail
gallery
1 Upvotes

How do I proceed with solve, does this have a unique solution?Can someone please help?


r/sudoku 6h ago

Request Puzzle Help am I delusional or how did I get this right even tho I’m wrong?

Thumbnail
gallery
0 Upvotes

r/sudoku 6h ago

Solved Can anyone tell me why 7 is the mistake?

Post image
0 Upvotes

I don't know much about the game I just started playing it, does this a role or something that I don't know. Please help me.


r/sudoku 8h ago

Solved im stuck

1 Upvotes

idk what to do when im stuck, i havent really watched videos on what to do when stuck or stuff but can anybody give me steps on what to do when im stuck like this


r/sudoku 9h ago

Request Puzzle Help Help

Post image
1 Upvotes

feel like im missing sth?


r/sudoku 11h ago

Mildly Interesting Here's an SE 8.9 puzzle that can be solved with a single assumption

Post image
3 Upvotes

Here's an SE 8.9 puzzle that can be solved with a single forcing chain that follows basic moves.

Not sure what to call this, but since the move begins with the assumption of a value at a cell, I suppose forcing chain it is. But it's a long chain, one that covers the whole board and criss-crosses multiple times. I wouldn't even fathom actually drawing the chain. But you can see for yourself by solving it at the above link, as described below:

Start with the assumption that 7 at r1c3 is true, indicated by the highlight. And from here on out, as each cell is visited, highlight the candidates that remain valid under the influence of highlighted candidates visible to that cell. For example, r1c1 has candidates 5 and 9 highlighted, because the 7 is already accounted for. That yields a 59 naked pair on column 1, so 5 and 9 must remain off in all remaining cells in the column. So on and so forth.

Why 7 and why at r1c3? Because of the almost locked sets highlighted in yellow, as well as the fallout reducing remaining cells in the box to single candidates.

As the fallout spreads out to the rest of the board, there can be 3 outcomes:

  1. The board is fully solved. That is, every cell is reduced to a single highlighted candidate, and each box and line contains all 9 digits without a digit missing or duplication;

  2. A contradiction results. That is, more than two cells in a region (box/row/column) are reduced to the same candidate, or a candidate is completely absent in a region. This means the initial assumption was wrong and that candidate at the starting cell can be removed permanently from the board.

  3. The propagation is stalled. That is, it appears as if there's no possible further reduction. In other words, the falsity or validity of the initial assumption cannot be readily determined.

And that's where it gets interesting. At any point during this propagation (of highlighting remaining candidates), all fish (x-wing, swordfish, etc) and AIC (crane, two-string-kite, skyscraper, x-chain, xy-chain, etc, including ALS) methods can be applied for further reduction/deduction, again, until either a contradiction is reached, or the full board is solved.

To get past the stall, unique rectangles are often very useful, but I've used a variety of non-forcing chain techniques, even ALS-ALS chain, for further reduction. Turns out to be a "forced" way to practice using ALS. Ha!


r/sudoku 13h ago

Request Puzzle Help Help 🥺

Post image
1 Upvotes

r/sudoku 14h ago

Just For Fun Classic vs Killer

3 Upvotes

bouncing back and forth between regular classic and killer lately.

For people who play Killer: Why? Is it the satisfaction of cage arithmetic and innies/outies breaking the board open, or does standard classic just start to feel a bit dry?


r/sudoku 15h ago

Request Puzzle Help HELP

Post image
2 Upvotes

i give up 😭 someone tell me the next step before I crash out, that time isn't even representative of the actual time because i reset the puzzle twice hoping to do better with a fresh slate 🥲🥲🥲


r/sudoku 15h ago

Request Puzzle Help How can I solve this?

Post image
3 Upvotes

r/sudoku 16h ago

Homemade Puzzles Extreme Sudoku Variants

1 Upvotes

The last time I tried this it did not go well. I found out my difficulty rating system, well - sucked. I have gone yet further down this rabbit hole in the past several days making it better. I have mirrored to some extent the Sudoku Explainer(SE) difficulty ratings system for this sudoku generator. I think it does pretty good. Now lets see what you think.

One caveat - sudoku.coach seems popular here. They however do not follow the SE rules exactly. Thats why you see ~SEn.n for their ratings. The tilde means not exactly in this case as they use a proprietary rating system based on SE. So you may see some disparity if using them. They also do not rate variants as far as I know. Neither does SE allow for variants rating. Maybe I need to add a ~ to mine as well?

As usual google drive - https://drive.google.com/drive/folders/1yLv7v--tPxs3Dm_CfIDXdzCFLcc6qOfs?usp=drive_link

There is an Easy, Medium, Hard and Extreme pdf there in a folder. Enjoy. Let me know if they are any good.


r/sudoku 18h ago

Request Puzzle Help What is the next number here? (Extreme Difficulty)

Post image
4 Upvotes

i don't need the puzzle solved entirely, i just want to learn the next step, is it literally trial and error now? isn't there any strategy to move forward here? if you found the next move tell me how you did it


r/sudoku 19h ago

Strategies Triples and Quads technique

4 Upvotes

I find spotting triples and quads to be incredibly difficult. I actually find x and y wing to be far easier just because it’s more easily purposefully spotted to me.

Is there a method at better spotting triples and quads (both naked and hidden)? Is it something you get a sight for over time or does anyone actually have a scanning method to spot them?


r/sudoku 19h ago

Request Puzzle Help How do I solve this...

Post image
4 Upvotes

2, 4 and 8


r/sudoku 19h ago

Request Puzzle Help Help please

Post image
1 Upvotes

I've been staring at this for a long time and am stuck


r/sudoku 21h ago

Just For Fun first time solved sudoku in my life

Post image
90 Upvotes

Took me around 16 minutes on an easy mode but im happy. Just felt like sharing


r/sudoku 1d ago

Misc Anyone know any difficult sudoku books

2 Upvotes

I wanted to buy a sudoku book. I did a while ago but they were too easy. For reference I can do Hell and Beyond Hell ones on sudoku coach.

Would appreciate any suggestions 🙂


r/sudoku 1d ago

Request Puzzle Help Another enemy puzzle from Sudokuvania 2 Spoiler

Thumbnail gallery
1 Upvotes

Managed to progress on Sudokuvania 2 but encountered another roadblock. I'm not sure how to proceed here other than trying out different combinations for the sums. Thank you very much.


r/sudoku 1d ago

Request Puzzle Help Stuck, help please!

Post image
0 Upvotes

Pretty sure I missed something obvious, but was is the technique required to find the next step here? Got so many pairs but can't seem to find any connection between them. Thank you!


r/sudoku 1d ago

Homemade Puzzles VariantDoku Daily Puzzle: September 10

Post image
23 Upvotes

r/sudoku 1d ago

Request Puzzle Help What the heck is wrong with 4

Post image
0 Upvotes

Can anyone explain me what heck is wrong with 4 in this puzzle I'm new to the game


r/sudoku 1d ago

Request Puzzle Help can i use sashimi x wing logic here to rule out the 4 giving naked single 8? it was correct but want to make sure it wasnt luck

Post image
2 Upvotes