... by: Norman Powell
This is solvable with your solver.Here is my solution path as an alternative (Rows numbered, Columns lettered, read from the bottom up),
Forcing Networks do the heavy lifting:
Solved Cells and Hidden Singles mop up.
XY-Cycles Value 3 of Cell G5 can see both ends of Chain - Eliminate
Rectangular Elimination Value 1 ON in Cell E6 and Strong Link E2 A2 would eliminate all 1s from Box 4 - so Eliminate
Hidden Pairs Hidden Pair in Box 6, for Values: 3 6 in Cells: I4 G5
X-Wing FH18 for Value 3
Hidden Singles In Box 3 I3 = 9.
In Column 6 F2 = 9.
Hidden Pairs Hidden Pair in Row 8, for Values: 3 5 in Cells: F8 H8
Hidden Singles In Box 9 G8 = 1.
In Column 7 G9 = 7.
WXYZ-Wing Hinge H8 Corners G8 H5 G9 Constrained Values 3 5 1
Eliminate Unconstrained Value 7 from Cells: H7 G6
Y-Wing Hinge H5 Corners C5 H8 Constrained Values 5 7
Eliminate Unconstrained Value 3 from Cells: C8
Alt. Inf. Chains Value 3 of Cell H5 has weak links to both ends of the chain
This possibility would cause a contradiction - Eliminate
WXYZ-Wing Hinge C6 Corners B6 C1 B4 Constrained Values 1 9 7
Eliminate Unconstrained Value 4 from Cells: C5
Hidden Singles In Row 1 G1 = 5.
X-Wing FH58 for Value 5
Hidden Singles In Column 2 B8 = 2.
Solved Cells Cell B1 = 6
Forcing Networks Value 5 in Row 8 Column G cannot be ON so eliminate
Contradiction: No possibilities left for Row 9 Column E
Value 6 in Row 8 Column B cannot be ON so eliminate
Contradiction: More than one Value 2 ON in Row 4
Value 7 in Row 6 Column C cannot be ON so eliminate
Contradiction: No possibilities left for Row 7 Column E
Value 2 in Row 6 Column B cannot be ON so eliminate
Contradiction: More than one Value ON in Row 4 Column A
Value 2 in Row 5 Column H cannot be ON so eliminate
Contradiction: More than one Value 4 ON in Column I
Value 5 in Row 5 Column G cannot be ON so eliminate
Contradiction: More than one Value 2 ON in Column A
Value 2 in Row 5 Column G cannot be ON so eliminate
Contradiction: More than one Value 5 ON in Column H
Value 2 in Row 4 Column B cannot be ON so eliminate
Contradiction: No possibilities left for Value 5 in Row 8
Value 5 in Row 3 Column G cannot be ON so eliminate
Contradiction: More than one Value 2 ON in Row 4
Value 6 in Row 1 Column C cannot be ON so eliminate
Contradiction: More than one Value 2 ON in Row 4
Value 6 in Row 1 Column B cannot be OFF so eliminate other values
Contradiction: More than one Value 2 ON in Row 4
Value 5 in Row 1 Column B cannot be ON so eliminate
Contradiction: More than one Value 2 ON in Row 4
Value 4 in Row 1 Column B cannot be ON so eliminate
Contradiction: More than one Value 2 ON in Row 4
Grouped Alt. Inf. Chains Value 7 of Cell G5 has weak links to both ends of the chain
This possibility would cause a contradiction - Eliminate
Forcing Networks Value 8 in Row 7 Column A cannot be ON so eliminate
Contradiction: More than one Value 2 ON in Row 6
Value 7 in Row 4 Column E cannot be ON so eliminate
Contradiction: No possibilities left for Row 1 Column F
Value 2 in Row 2 Column I cannot be ON so eliminate
Contradiction: More than one Value ON in Row 1 Column B
Value 1 in Row 2 Column C cannot be ON so eliminate
Contradiction: No possibilities left for Value 8 in Column C
Forcing Networks Value 5 in Row 9 Column G cannot be ON so eliminate
Contradiction: No possibilities left for Value 2 in Row 1
Value 5 in Row 7 Column H cannot be ON so eliminate
Contradiction: No possibilities left for Value 2 in Row 5
Value 9 in Row 2 Column I cannot be ON so eliminate
Contradiction: No possibilities left for Value 1 in Row 6
Value 7 in Row 2 Column F cannot be ON so eliminate
Contradiction: More than one Value 2 ON in Column A
Forcing Networks Value 5 in Row 3 Column I cannot be ON so eliminate
Contradiction: More than one Value 6 ON in Row 2
Forcing Networks Value 9 in Row 8 Column B cannot be ON so eliminate
Contradiction: More than one Value ON in Row 2 Column C
Value 6 in Row 2 Column C cannot be ON so eliminate
Contradiction: More than one Value 5 ON in Box 5
Value 6 in Row 1 Column G cannot be ON so eliminate
Contradiction: More than one Value 5 ON in Box 5