Hidden Unique Rectangle

Hard

A more subtle form where the deadly pattern is detected indirectly through hidden candidates.

How It Works

Unlike standard Unique Rectangle where the two candidates are visible in all four cells, the hidden variant detects the deadly pattern indirectly. The rectangle candidates are "hidden" among other candidates, making this harder to spot.

Example

5	4	7	9	3	8	6	2	17
9	6	8	1	7	2	4	5	3
2	3	27	4	5	6	127	8	9
1	2	3	5	4	7	8	9	6
4	5	6	2	8	9	3	7	1
7	8	9	3	6	1	2	4	5
3	1	27	7	9	4	257	6	8
6	7	24	8	1	5	9	3	24
8	9	14	6	2	3	157	1	45

Key cells of the techniqueCells where elimination is appliedCandidate to be placedEliminated candidate (crossed out)

5	4	7	9	3	8	6	2	17
9	6	8	1	7	2	4	5	3
2	3	27	4	5	6	127	8	9
1	2	3	5	4	7	8	9	6
4	5	6	2	8	9	3	7	1
7	8	9	3	6	1	2	4	5
3	1	27	7	9	4	257	6	8
6	7	24	8	1	5	9	3	24
8	9	14	6	2	3	157	1	45

5	4	7	9	3	8	6	2	17
9	6	8	1	7	2	4	5	3
2	3	27	4	5	6	127	8	9
1	2	3	5	4	7	8	9	6
4	5	6	2	8	9	3	7	1
7	8	9	3	6	1	2	4	5
3	1	27	7	9	4	257	6	8
6	7	24	8	1	5	9	3	24
8	9	14	6	2	3	157	1	45

5	4	7	9	3	8	6	2	17
9	6	8	1	7	2	4	5	3
2	3	27	4	5	6	127	8	9
1	2	3	5	4	7	8	9	6
4	5	6	2	8	9	3	7	1
7	8	9	3	6	1	2	4	5
3	1	27	7	9	4	257	6	8
6	7	24	8	1	5	9	3	24
8	9	14	6	2	3	157	1	45