Step-by-Step Solution
for Friday 16th May Tricky
Before
Step
After
For box 1, candidates for 5 are all in column 3, so you can remove candidates from other blocks.
For box 9, candidates for 3 are all in column 7, so you can remove candidates from other blocks.
Candidates for 5 in boxes 1 and 3 force the candidates in box 2 to be in the remaining line.
Candidates for 4 in boxes 1 and 7 force the candidates in box 4 to be in the remaining line.
Candidates for 4 in boxes 2 and 8 force the candidates in box 5 to be in the remaining line.
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