by tso » Sun Feb 05, 2006 2:30 am
This puzzle requires nothing but singles to solve.
At this point, there's only one place for a 1 in column 5, only one place for a one in box 8, only one place for a 3 in box 9, only one place for a 3 in row 8, only one place for a 6 in box 1, only one place for a 6 in row 2, only one place for a 6 in box 8, only one place for a 6 in row 7, only one place for a 7 in box 5, only one place for a 7 in column 4, only one place for a 9 in box 1, only one place for a 9 in column 2 -- and there's only one number that can go in r9c4.