Step-by-Step Solution
for Sunday 22nd December Tricky
Before
Step
After
For box 9, candidates for 9 are all in column 7, so you can remove candidates from other blocks.
For box 2, candidates for 3 are all in row 1, so you can remove candidates from other blocks.
For box 3, candidates for 3 are all in row 2, so you can remove candidates from other blocks.
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