Shikaku Killer
(Published on 18. February 2025, 20:18 by Ennead)
This puzzle was created for the CTC 'Secret Santa' puzzle gift exchange. Reproduced here with the kind permission of the recipient MrDanH.
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Normal sudoku rules apply. Divide the entire grid into rectangles each containing a single circle and a single cell containing a ‘?’. The digit in the circle gives the number of cells in the rectangle. Digits cannot repeat in rectangles and each rectangle’s digits sum to one of 10, 20, 30 and X (where X is to be determined by the solver).
Solution code: Row 3 left-right followed by column 3 top-bottom.
Comments
on 1. March 2025, 00:06 by novato
Really fun solve, a few twisty bits but never felt too stuck. Some really clever logic too. Great puzzle
on 20. February 2025, 14:09 by Franktothejay
Great puzzle. I really enjoyed the logic on this one--and it didn't seem quite as hard as advertised.
on 20. February 2025, 03:14 by yttrio
Really nice puzzle! I particularly liked the process of determining the 4th possible sum. There were some tricky steps in the mid-solve, but it never felt unfair.
on 20. February 2025, 00:50 by JAnderson
Never done a shikaku before so you could imagine my frustration at trying to find the secret amidst the rule set. I did eventually find out that secret and from then on it was a fun solve and still a fair challenge after placing the rectangles
on 19. February 2025, 12:47 by Bankey
Lovely puzzle. Thanks, @ Ennead :).
on 19. February 2025, 10:47 by Snookerfan
Very nice! Super fun puzzle. Thank you
on 19. February 2025, 08:12 by Ennead
Edit to rules for clarification.
