Seeing Double
(Published on 13. February 2026, 23:31 by Sedum)
Place 1-9 in each row, column and 3x3 region.
Doubler: One digit is a doubler, it is up to the solver to determine which digit. The value of the DOUBLER is doubled, as doublers do.
Positive Diagonal: Digits cannot repeat along the positive diagonal thin blue line.
Region Sum Lines: For each thick blue line, VALUES on the line have an equal sum N within each box it passes through.
Modified X-sums: Clues at the edge of the grid show the sum of the VALUES of the first X DIGITS, where X is the first seen DIGIT.
The doubler DIGIT is first seen by an x-sum exactly once.
All other DIGITS first seen by an x-sum are seen by x-sum clues exactly twice.
Example: Given an x-sum clue of 2, a solver could determine that the doubler must be the DIGIT 1, which has a VALUE of 2 for the sum of the x-sum clue.
Play on SudokuPad
Doubler: One digit is a doubler, it is up to the solver to determine which digit. The value of the DOUBLER is doubled, as doublers do.
Positive Diagonal: Digits cannot repeat along the positive diagonal thin blue line.
Region Sum Lines: For each thick blue line, VALUES on the line have an equal sum N within each box it passes through.
Modified X-sums: Clues at the edge of the grid show the sum of the VALUES of the first X DIGITS, where X is the first seen DIGIT.
The doubler DIGIT is first seen by an x-sum exactly once.
All other DIGITS first seen by an x-sum are seen by x-sum clues exactly twice.
Example: Given an x-sum clue of 2, a solver could determine that the doubler must be the DIGIT 1, which has a VALUE of 2 for the sum of the x-sum clue.
Play on SudokuPad
Solution code: Row 9 (left to right)
Last changed on on 15. February 2026, 18:47
Solved by miranda_9, SKORP17, gdc, caiogi, SecondBlue
Comments
on 15. February 2026, 18:47 by Sedum
Updating difficulty to 4 star
