The New Sudoku Players' Forum

by **m_b_metcalf** » Wed May 31, 2023 7:03 am

Code: Select all: . . 1 2 3 . . . 4 . 5 . . . 1 . . . 6 . . . . . 7 . . . . . . . 8 . . 2 . . 3 1 6 . . . . . . . . . 9 . . 6 4 . . . . . 5 . . . 7 . . . 3 . . . . . 5 9 1 . . . 8 #1, medium ..123...4.5...1...6.....7.......8..2..316.........9..64.....5...7...3.....591...8 ED=7.2/7.2/6.6

Code: Select all: . . 1 2 3 . . . 4 . 4 . . . 1 . . . 2 . . . . . 7 . . . . . . . 8 . . 5 . . 9 3 1 . . . . . . . . . 9 . . 2 7 . . . . . 4 . . . 8 . . . 3 . . . . . 3 4 5 . . . 9 #2, very hard ..123...4.4...1...2.....7.......8..5..931.........9..27.....4...8...3.....345...9 ED=9.3/9.3/2.6

The 'spine' in c9 is required to provide sufficient clues.

by **Cenoman** » Thu Jun 01, 2023 8:21 pm

#1 Four steps

Code: Select all: +---------------------------+-----------------------+--------------------------+ | 789 89 1 | 2 3 a56-7 | 689 b5689 4 | | 23789 5 24789 | 4678 4789 1 | 23689 23689 39 | | 6 23489 2489 | 458 4589 45 | 7 123589 c1359 | +---------------------------+-----------------------+--------------------------+ | 1579 1469 4679 | 3457 457 8 | 1349 134579 2 | | 25789 2489 3 | 1 6 245-7 | 489 45789 d579 | | 12578 1248 2478 | 3457 2457 9 | 1348 134578 6 | +---------------------------+-----------------------+--------------------------+ | 4 123689 2689 | 678 278 267 | 5 123679 e1379 | | 1289 7 2689 | 4568 2458 3 | 12469 12469 19 | | 23 236 5 | 9 1 g2467 | 2346 f23467 8 | +---------------------------+-----------------------+--------------------------+

1. (5)r1c6 = r1c8 - r3c9 = (5-*7)r5c9 = r7c9 - r9c8 = (7)r9c6 => -7 r1c6, r5c6*; lcls, 1 placement

Code: Select all: +-------------------------+-----------------------+--------------------------+ | 7 89 1 | 2 3 b56 | 689 a5689 4 | | 2389 5 2489 | c4678 4789 1 | 23689 23689 39 | | 6 23489 2489 | e458 4589 e45 | 7 12389-5 139-5 | +-------------------------+-----------------------+--------------------------+ | 159 1469 4679 | 3457 457 8 | 1349 13459 2 | | 2589 2489 3 | 1 6 245 | 489 45789 579 | | 1258 1248 2478 | 3457 2457 9 | 1348 13458 6 | +-------------------------+-----------------------+--------------------------+ | 4 123689 2689 | d68 28 267 | 5 123679 1379 | | 1289 7 2689 | 4568 2458 3 | 12469 12469 19 | | 23 236 5 | 9 1 2467 | 2346 23467 8 | +-------------------------+-----------------------+--------------------------+

2. (5)r1c8 = (5-6)r1c6 = r2c4 - (6=8)r7c4 - (8=45)r3c46 => -5 r3c89; lcls, 13 placements

Code: Select all: +-----------------------+-------------------+----------------------+ | 7 89* 1 | 2 3 6 | 89* 5 4 | | 2389 5 248 | 478 479 1 | 26 2689 39 | | 6 b23489 248 | 48 49 5 | 7 d1289 c139 | +-----------------------+-------------------+----------------------+ | 159 146-9 467 | 357 57 8 | 134 1349 2 | | 289* 289* 3 | 1 6 4 | 89* 7 5 | | 158 148 478 | 357 2 9 | 134 1348 6 | +-----------------------+-------------------+----------------------+ | 4 a13 9 | 6 8 2 | 5 3-1 7 | | 128 7 268 | 45 45 3 | 126 1269 19 | | 23 236 5 | 9 1 7 | 2346 2346 8 | +-----------------------+-------------------+----------------------+

3. M2-Wing: (1=3)r7c2 - r3c2 = (3-1)r3c9 = (1)r3c8 => -1 r7c8; lcls, 2 placements
4. Finned X-Wing: (9)r1c2 = r1c7 - r5c7 = r5c12 => -9 r4c2; ste

The Digit 3