Please note that in box 4 (LH middle box of 9 x 9 cells) that there are only two cells that can contain the options 7 & 8. Well, this is sort of the place to do this. MARK UNSOLVED CELLS WITH OPTIONS THAT CANNOT EXIST IN THOSE CELLS … Now your grid should look like Example 50.1 below: Example # 50.1 The first obvious answer is C6R9 (cell in column 6, row 9) = 8. Start with the 1’s to see if there are any obvious 1-choice answers. FILL IN THE OPTIONS FOR THE UNSOLVED CELLS.MARK UNSOLVED CELLS WITH OPTIONS THAT CANNOT EXIST IN THOSE CELLS.

Prior to utilizing techniques first complete the 4 Steps of Puzzle Preparation … Dan LeKander's Sudoku book - a must for your island bookcase! May 2018, June 2018, July 2018, August 2018, September 2018, October 2018, November 2018, December 2018, January 2019 and February 2019.Īs a reminder, the basic rules of Sudoku are that the numbers 1-9 must be contained and cannot be repeated in a row, column, or box, and there can only be one solution to the puzzle. Steps 1-5 are relatively common techniques and are explained in the TI LIFE articles above. Step 7: DAN’S CLOSE RELATIONSHIP CHALLENGE Step 4: XY-Wings & XYZ Wings – December 2015 Step 3: Sudoku Gordonian Rectangles and Polygons – November 2015 Step 2: Turbos & Interaction – October 2015 Step 1: Sudoku Pairs, Triplets and Quads – September 2015 Once you have completed the puzzle, to the extent that you have filled-in all obvious answers and have written all potential options across the top of the unsolved cells (PUZZLE PREPARATION), Dan recommends the following Steps to complete the puzzle. You may learn the most when you tackle it yourself before looking at my solution! Puzzle # 50ĭAN’S 8-STEP APPROACH TO SOLVING ALL SUDOKU PUZZLES In keeping with the tradition of tackling difficult puzzles, Puzzle #50 is no exception. So, treat yourself to uninterrupted Sudoku experiences whenever you are solving Sudoku puzzles! There is no room for distractions or being in a hurry. What I find is that you must be 100% engaged when you are doing a puzzle. What! How did that happen? You just have to laugh at yourself. I paused, looked at the puzzle, and saw two 6’s in row 7. The other day I was about 80% complete on a difficult puzzle.

Sudoku puzzle solving