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Sudoku - Extra Diabolical — Solution #2

Difficulty: EXPERT Clues: 26 Hardest: BACKTRACKING 63 steps
0 / 63
NAKED SINGLE #1 R2C9 = 6 (only candidate)
NAKED SINGLE #2 R1C9 = 7 (only candidate)
NAKED SINGLE #3 R3C9 = 1 (only candidate)
NAKED SINGLE #4 R6C9 = 2 (only candidate)
NAKED SINGLE #5 R7C9 = 3 (only candidate)
NAKED SINGLE #6 R9C9 = 9 (only candidate)
HIDDEN SINGLE #7 R1C5 = 9 (only place for 9 in Row 1)
HIDDEN SINGLE #8 R6C5 = 5 (only place for 5 in Row 6)
HIDDEN SINGLE #9 R6C2 = 7 (only place for 7 in Row 6)
HIDDEN SINGLE #10 R4C5 = 7 (only place for 7 in Row 4)
HIDDEN SINGLE #11 R7C2 = 5 (only place for 5 in Row 7)
HIDDEN SINGLE #12 R2C7 = 5 (only place for 5 in Row 2)
HIDDEN SINGLE #13 R7C8 = 7 (only place for 7 in Row 7)
HIDDEN SINGLE #14 R9C5 = 4 (only place for 4 in Row 9)
NAKED SINGLE #15 R2C5 = 8 (only candidate)
NAKED SINGLE #16 R2C2 = 4 (only candidate)
HIDDEN SINGLE #17 R9C3 = 3 (only place for 3 in Row 9)
HIDDEN SINGLE #18 R3C2 = 3 (only place for 3 in Row 3)
HIDDEN SINGLE #19 R8C5 = 3 (only place for 3 in Row 8)
HIDDEN SINGLE #20 R5C4 = 3 (only place for 3 in Row 5)
X WING #21 4 in Rows 3,5 at Cols 6,8; eliminate from 4 cell(s)
XY WING #22 Pivot R7C5{1,6}, pincers R3C5 & R7C3; eliminate 2 from 1 cell(s)
BACKTRACKING #23 Try R1C4 = 6 (trial and error)
NAKED SINGLE #24 R3C5 = 2 (only candidate)
NAKED SINGLE #25 R1C6 = 5 (only candidate)
NAKED SINGLE #26 R3C6 = 4 (only candidate)
NAKED SINGLE #27 R3C8 = 8 (only candidate)
NAKED SINGLE #28 R1C7 = 4 (only candidate)
NAKED SINGLE #29 R3C3 = 6 (only candidate)
NAKED SINGLE #30 R3C1 = 5 (only candidate)
HIDDEN SINGLE #31 R5C8 = 4 (only place for 4 in Row 5)
HIDDEN SINGLE #32 R4C8 = 9 (only place for 9 in Col 8)
NAKED PAIR #33 R8C6 & R8C8 share {1,6}; eliminate from 3 cell(s)
XY WING #34 Pivot R7C3{1,2}, pincers R1C3 & R9C1; eliminate 8 from 1 cell(s)
NAKED SINGLE #35 R1C1 = 2 (only candidate)
NAKED SINGLE #36 R1C3 = 8 (only candidate)
SIMPLE COLORING #37 Coloring (trap): 1 — cell(s) see both colors; eliminate from 1 cell(s)
LOCKED CANDIDATES POINTING #38 1 in Box 5 → Row 5; eliminate from 1 cell(s)
SIMPLE COLORING #39 Coloring (trap): 1 — cell(s) see both colors; eliminate from 1 cell(s)
NAKED SINGLE #40 R7C3 = 2 (only candidate)
HIDDEN SINGLE #41 R8C7 = 2 (only place for 2 in Row 8)
HIDDEN SINGLE #42 R9C7 = 8 (only place for 8 in Col 7)
NAKED SINGLE #43 R9C1 = 1 (only candidate)
SIMPLE COLORING #44 Coloring (wrap): 6 — color group contradicts; eliminate from 6 cell(s)
NAKED SINGLE #45 R4C6 = 2 (only candidate)
NAKED SINGLE #46 R4C2 = 8 (only candidate)
NAKED SINGLE #47 R4C4 = 4 (only candidate)
NAKED SINGLE #48 R4C3 = 1 (only candidate)
NAKED SINGLE #49 R4C7 = 6 (only candidate)
NAKED SINGLE #50 R5C1 = 9 (only candidate)
NAKED SINGLE #51 R5C2 = 2 (only candidate)
NAKED SINGLE #52 R5C5 = 1 (only candidate)
NAKED SINGLE #53 R5C6 = 6 (only candidate)
NAKED SINGLE #54 R6C1 = 6 (only candidate)
NAKED SINGLE #55 R6C3 = 4 (only candidate)
NAKED SINGLE #56 R6C4 = 8 (only candidate)
NAKED SINGLE #57 R6C8 = 1 (only candidate)
NAKED SINGLE #58 R7C5 = 6 (only candidate)
NAKED SINGLE #59 R7C7 = 1 (only candidate)
NAKED SINGLE #60 R8C1 = 8 (only candidate)
NAKED SINGLE #61 R8C2 = 9 (only candidate)
NAKED SINGLE #62 R8C6 = 1 (only candidate)
NAKED SINGLE #63 R8C8 = 6 (only candidate)