The New Sudoku Players' Forum

[200e200w]

Code: Select all

4 7 .|. . .|. . .
. 2 1|4 . .|. . .
6 . 3|7 . 1|. . 8
-----+-----+-----
. . .|. 2 .|8 . 5
. . .|. . .|. 6 1
. . .|. 1 .|4 . 9
-----+-----+-----
8 . 9|2 . 3|. . 6
. 6 4|5 . .|. . .
2 3 .|. . .|. . .


200e200w

[SpAce]

This is my unedited p&p solution (no backdoors checked). So, it's exactly the steps I happened to execute while solving, which means it's not optimized for either efficiency or simplicity (obviously).

1. AIC: (8)r6c2 = (8-4)r5c2 = (4-5)r5c6 = (5)r6c6 => -5 r6c2
2. W-Wing(?): (9=5)r9c7 - r9c3 = r7c2 - r3c2 = r2c1 - (5=9)r2c8 => -9 r1c7, r89c8
3. Kraken Cell r8c7 => -5 r2c8 (*)
4. XY-Wing: (6=7)r4c3 - (7=3)r6c1 - (3=6)r6c4 => -6 r4c46, r6c3
5. AIC: (4)r4c6 = (4-1)r4c2 = r8c2 - (1=7)r8c1 - (7=9)r8c6 => -9 r4c6
6. AIC: (9)r4c1 = (9-3)r4c4 = r6c4 - (3=7)r6c1 - (7=1)r8c1 => -1 r4c1
7. AIC(?): (3)r4c1 =[BUG+2]= (7)r5c1 => -7 r4c1

(*) Step 3:

Code: Select all

(1)r8c7 - (1=5)r1c7 - (5)r2c8
 ||
(3)r8c7 - (3=7)r5c7 - (7=9)r5c5 - (9=5)r3c5 - r3c2 = r2c1 - (5)r2c8
 ||
(9)r8c7 - (9=5)r9c7 - r9c3 = r7c2 - r3c2 = r2c1 - (5)r2c8