Posts

Sudokuwiki.org's Weekly 'Unsolvable' Sudoku #648

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   In this post I'll be tackling the weekly "Unsolvable" puzzle from  SudokuWiki . This week's puzzle was provided by Andrew Stuart. 

Sudokuwiki.org's Weekly 'Unsolvable' Sudoku #647

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  In this post I'll be tackling the weekly "Unsolvable" puzzle from  SudokuWiki . This week's puzzle was provided by Andrew Stuart. 

Sudokuwiki.org's Weekly 'Unsolvable' Sudoku #646

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In this post I'll be tackling the weekly "Unsolvable" puzzle from  SudokuWiki . This week's puzzle was provided by Andrew Stuart. 

SE 9.0 from Reddit 2025-05-15

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u/Ok_Application5897 posted this puzzle on the Reddit today:

8.9 from Reddit 2025-05-13

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 Someone on the r/Sudoku Reddit posted this puzzle innocently asking for help:

Sudokuwiki.org's Weekly 'Unsolvable' Sudoku #645

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   In this post I'll be tackling the weekly "Unsolvable" puzzle from  SudokuWiki . This week's puzzle was provided by Andrew Stuart. 

Sudokuwiki.org's Weekly 'Unsolvable' Sudoku #644

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  In this post I'll be tackling the weekly "Unsolvable" puzzle from  SudokuWiki . This week's puzzle was provided by Richard Kröger. 

Sudokuwiki.org's Weekly 'Unsolvable' Sudoku #642

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In this post I'll be tackling the weekly "Unsolvable" puzzle from  SudokuWiki . This week's puzzle was provided by Richard Kröger. 

Dual AALS link

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In this post I will showcase a rather interesting interaction between two AALS that share a cell. This came up within an SE 8.3 puzzle I was solving and delighted me with its simplicity and its practicality (it immediately reduced the puzzle to basics). It is very similar to Sue de Coq. I'm sure it's known but I've never seen it brought up before. Typically when chaining off AALS, the easiest option tends to be to use region-wise interactions with ALS weakly linking 2 candidates at once. 

Sudokuwiki.org's Weekly 'Unsolvable' Sudoku #640

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 In this post I'll be tackling the weekly "Unsolvable" puzzle from  SudokuWiki . This week's puzzle was provided by Richard Kröger, as with last week's. 

Impossible pattern chaining in an SE 9.0 challenge from Reddit

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Here's a puzzle generated by Sudoku.Coach and posted by u/ddalbabo on Reddit. SC's "Beyond Hell" grids are always a treat, often on the very edge of requiring Forcing Chains.

Sudokuwiki.org's Weekly 'Unsolvable' Sudoku #639

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  In this post I'll be tackling the weekly "Unsolvable" puzzle from  SudokuWiki . This week's puzzle was provided by Richard Kröger. 

Solving "Impossible #1" with DoF>1 AIC

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I've been learning advanced Sudoku tactics for about 2 years now and lately I've been venturing into the world of branched AIC. It's very work-intensive to identify useful examples, but the results are equally rewarding.