* Look at box 8, concentrate at the number 5, now look at row 9 * Look at box 5, focus on the numbers: 3, 4 and 8 * now take a new look at column 5, and combine that with the possibilities for 3, 4, and 8 in box 5. (you can exclude 3, 4 and 8 from several cells in column 5) * take a look at row 9, look closely at the numbers 1, 5, 6 * now look at column 9. if you've done the previous steps correctly then you should be able to fill in a number...
1. Box 8 5 must be r9 c 4 or 5 2. 3,4 and 8 must occupy column 5 in box 5 3. therefore r1 c5 and r9 c5 must have 5,6. 4. don't see anything special about number 1... 5. still cannot place anything in c9