The New Sudoku Players' Forum

[hobiwan]

My solver returns a short XY-Chain for [r8c6]<>9. While reviewing the PM, it appears that this elimination might also be the result of an ALS using [r27c4]=149 and [r9c46]=179. Am I even close

Right on spot:
Almost Locked Set XZ-Rule: A=r9c46 - {179}, B=r27c4 - {149}, X=1, Z=9 => r8c6<>9

It could also be seen as an ALS-XY-Wing:
Almost Locked Set XY-Wing: A=r7c4 - {49}, B=r9c46 - {179}, C=r2c4 - {14}, Y,Z=1,4, X=9 => r8c6<>9

or as a Sue de Coq:
Sue de Coq: r79c4 - {1479} (r2c4 - {14}, r9c6 - {79}) => r8c6<>9

[daj95376]

hobiwan: Thanks for the useful information

[Draco]

Or, if you like, another short chain also cracks the puzzle:

r3c4=3 r5c4=5 r7c4=9 + r3c4=5 r1c4=3 r7c7=9 ==> r7c1<>9

Cheers...

- drac