12:21 am
						irv
						
						Done. very easy for expert
					 
									
						8:29 am
						spellacked
						
						Since this one ended up with a small number of unknowns at the point where I wanted to guess, I went to check how https://www.sudokuwiki.org/sudoku.htm would solve it.  And I can see the logic of the XY-Chains it suggests, the problem is that without exhaustive searches that computers find easy to do, how would I locate those XY-Chains.  Is there a trick to finding those  Once you find enough of those, the remaining dozen numbers are all forced and easy.
					 
									
						10:56 am
						 gman
						
						Spellacked: let me know if you find a clue cause I dont think theres enough time in the day to find one X/Y chain much less the several that might be required to solve the nasty expert puzzles.  No tricks, I believe, just brute computing.  Thats why I end up guessing on most Experts and some hard puzzles.  Happy Friday
					 
									
						11:02 am
						KnightTime
						
						there are 2 x-wings in this puzzle one of which has an obvious non-value on one of the corners, i.e. it leads to duplicate numbers if the value is chosen, therefore choosing the other value solves the puzzle.
					 
									
						11:04 am
						 gman
						
						Thanx KT.  I have15 numbers solved and slowing down.  Might have to go green when I get back to it.