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`#1//B4,N`

.51.247894728.9.6..9817.24.21948..3.86.29.4..74..619289847....2.269.8.74.37.4289.

I expect when solving by hand that SiseSuSo will do it the same way with 2xy-wings, but it needs first 2 xy-chains which are harder and then the xy-wings.

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`Pointing, Claiming | (3)b9c7 => (-3)r2c7`

XY_Chain r | (5=3)r3c9 (3=6)r3c1 (6=3)r1c1 (3=6)r1c4 (6=5)r9c4 [5] => (-5)r9c9

XY_Chain b | (5=3)r2c5 (3=6)r1c4 (6=5)r9c4 (5=1)r9c1 (1=5)r8c1 [5] => (-5)r8c5

XY-Wing r | (1=5)r2c7 (5=3)r2c5 (3=1)r8c5 [3] => (-1)r8c7

XY-Wing b | (1=5)r7c8 (5=3)r8c7 (3=1)r8c5 [3] => (-1)r7c5

Why checks it first for chains instead of wings which are lower rated?

There is a simple xy-wing to start with at R1C4,R2C5,R9C4: R1C4=3--> R2C5=5; R1C4=6--> R9C4=5; R78C5<>5