I just started playing this game with regularity recently. One strategy I like to use is trying to get all 9 of a number out of the way. So I will figure out where to put 7-9 of the 3s or 5s or 6s to get them out of the way.
However after I do that I notice there are always a few numbers that are barely on the board. Maybe there are eight 5s, but there are only two 1s on the board. Which means for each empty space, I have no idea where the 1 goes. I end up creating a bunch of empty spaces and having three or four numbers that are barely on the board, so now I don’t know where those numbers go.
I find this strategy helps me place numbers in the beginning of the game, but makes it harder by the middle of the game than when I do not use this strategy.
Is there a name for this strategy?
This isn’t a strategy. The strategy is whatever you’re using to figure out where the numbers are. It doesn’t matter what order you figure things out in.
My technique is pretty basic, and I’m probably the only person who does something so unsophisticated:
I start with 1 and move up to 9. For each number, I see if there are 3x3 blocks where the number can only be in 1 or 2 cells. If one, I put it in there, of course, and if it’s two, I “note” those two with the note function (or tiny pencil if it’s on paper). If it’s three or more, I don’t “note”. I move through all the numbers that way, then again to see if what I’ve done has made anything change.
Then it gets trickier. If there are two cells in a 3x3 block that have the same two numbers (2 and 4, for example), I know that those cells are closed, and I see if that opens up anything else for the rest of the block, or closes off anything else in other rows or columns. I check rows and columns that have a high number of known numbers in them to see if I can fill in any additional numbers. Last ditch thing, I see if I can spot any lone cells where only one number is possible.
When all of that fails, as it sometimes does in expert-level puzzles, I find a cell that has only two possibilities, pencil in one as a wild guess, and see if it takes me through or if it leads to a dead end. If it’s a dead end, backtrack and try the other number.
Anyway, from what I’ve seen, most people don’t have a problem “noting” when there are more than two possibilities in a 3x3 block, but I never do. I think that’s where I’m weird.
Not marketing here, but there is an app called “Enjoy Sudoku Daily” that I find quite amazing, when I’m in the sudoku mood.
It has a wide range of difficulties available. It permits “pencil marks”. It will unwind a “broken” puzzle until its solvable. It keeps all kinds of stats.
Best of all, it offers hints. Like “look for a ‘fish’”. What’s a ‘fish’, you ask? Well, it will give you a mini tutorial. Then if you still can’t find it, it shows it to you in your puzzle.
This app really upped my game.