Extended Unique Rectangle

Hard

Unique Rectangle extended to 6 or more cells; the deadly pattern principle applies to larger structures.

How It Works

Rectangle-like patterns spanning 6 or more cells. The deadly pattern principle is extended: if the structure would create multiple solutions, candidates that preserve uniqueness must be kept.

Example

4	7	9	6	1	5	2	38	38
6	38	38	2	9	4	38	1	7
1	2	5	3	7	8	4	6	9
2	13	3	59	5	67	8	9	6
5	38	38	8	3	9	358	7	2
8	9	7	1	2	6	3	45	45
3	46	1	7	6	2	9	58	48
7	8	2	9	4	1	6	35	3
9	46	4	5	8	3	17	25	1

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

4	7	9	6	1	5	2	38	38
6	38	38	2	9	4	38	1	7
1	2	5	3	7	8	4	6	9
2	13	3	59	5	67	8	9	6
5	38	38	8	3	9	358	7	2
8	9	7	1	2	6	3	45	45
3	46	1	7	6	2	9	58	48
7	8	2	9	4	1	6	35	3
9	46	4	5	8	3	17	25	1

4	7	9	6	1	5	2	38	38
6	38	38	2	9	4	38	1	7
1	2	5	3	7	8	4	6	9
2	13	3	59	5	67	8	9	6
5	38	38	8	3	9	358	7	2
8	9	7	1	2	6	3	45	45
3	46	1	7	6	2	9	58	48
7	8	2	9	4	1	6	35	3
9	46	4	5	8	3	17	25	1

4	7	9	6	1	5	2	38	38
6	38	38	2	9	4	38	1	7
1	2	5	3	7	8	4	6	9
2	13	3	59	5	67	8	9	6
5	38	38	8	3	9	358	7	2
8	9	7	1	2	6	3	45	45
3	46	1	7	6	2	9	58	48
7	8	2	9	4	1	6	35	3
9	46	4	5	8	3	17	25	1