Solve Sudoku (Without even thinking!)

Step 10 Lather, rinse repeat.

Eventually, you will find all those lonely numbers in thier rows, columns or groups.

Remember to draw those lines and circles in case you get interrupted.

Eventually you will solve the puzzle.

Compare our solution to the "Official Solution" found on the Sudoku.com site. See? A perfect match.

And you thought Sudoku was hard.

It's so easy, you don't even have to think!

Comments

[WillyTheKid]

I try to get everybody I know to play Killer Sudoku (or Sum-doku). So much more of a challenge than even the hard level sudokus. but still there is a system.. always a system, even if it is complex. no need to guess!

[bjohnson1]

You should only use a pen and no eraser! That is how to do Sudoku.

[bjarvis2]

I'm creating a C++ sudoku solver for practice, and this algorithm looks great for a square 1 starting place! There are probably more efficient methods for automation, but this algorithm is a systematic approach to what a human does, albeit (or although, depending on who you're talking to) very explicitly stated and discrete.

[chinmoy samant]

he thanxxxxxxx it was just mind-blowing'awesome............................

[cat20]

hey thanx ,this is wat exact solution i was searching for

[Pentacle]

Well, it definitely works! It just takes a long time to write everything in and erase it.

[zheyman]

Too tedious ?? Just one click fills them all in at http://www.SudokuByZol.com

Comprehensive and extremely efficient pencil-mark support and user interface.

Play never ending supply of puzzles (5 Levels), or enter your own puzzle using the Solver link or button.

[camcuru]

This is the very first step to solving Sudoku puzzles, but it will only get you so far.
This method will NOT be sufficient to solve 197 of the 200 Sudoku puzzles found in the Extreme Sudoku book by Antoine Alary ( sudoku.alary.org ).
Get that book if you want a real challenge, it even has the pencilmarks pre-printed in half of the puzzles, as most of the advanced Sudoku solving techniques make use of them.

[zheyman]

You can enter the puzzles from that book into http://www.SudokuByZol.com and solve them online using the techniques here and others.

Efficient keyboard or mouse user interface that won't get in your way.

Just click the Solver button or link.

[ToddisI]

Pure amazingness!!!!

[Snowbunny]

I picked up my first puzzle and applied this technique. I failed then copied the puzzle again and took my time. Unfortunately the puzzle was labeled "gold" or "Hard" and I still have a few squares left with a lot needing the same numbers. Is there some sort of "next step" or should I just "hit and miss" and take the "keep trying approach"? Any suggestions?

[amannuc]

No need to guess. If you are interested, I can provide additional clues.

[nafango22]

this doesnt work with very hard sudoku puzzles. the really tricky ones will make you randomly pick a number for a square and check to make sure it works in that square as you fill more in.

[amannuc]

I have done many "genius level" Sudokus without guessing. There is no need to guess. If you are interested, I'll put up the information on a wordpress blog that works for me.

[bullitje]

this is allot of work for something simple as a soduku. I just use a number by number approach , write on your paper , the number 1 trough 9 , and start with 1 , and follow trough, use the 2 obvious ways of elimination, (1 elimination form rows and collums, 2 elimination from square) and then you should solve all the easy one's. when you completeted a number , you scratch it away. the hard ones , you need to figure out 3 more ways of elimination. i can't describe them , but they use simple looking ahead. And about you have to pick a random number that is nonsense , you just have to look far ahead enough to see the consequences, with some practice you can look ahead 5-10 steps. There are chances that you see "pairs" of numbers , then scribble down the pairs, so you remember them quickly when you fill in 1 of the numbers.

[mendoza33]

Isnt this more work than it should be....?

[gpj]

I just tried this for an Evil rated sudoku. As other comment said, you don't get a solution for this degree of difficulty. However, I think this works as additional step: 1. After step 10, lather, rise, repeat you may not be left with single numbers. Find the group with just two squares empty, each with two numbers. At this point you have to guess. 2. Copy your paper exactly as you have it now, so if you guess wrong you can try again. 3. Guess the pair of numbers for the two squares. 4. Continue with the method above. If it works, you guessed right. If you guessed wrong, it will go wrong. If you guessed wrong, go back to your copy, guess the other way. This is still a mechanical solution, no thinking required. There's a lot of paper and writing though, I did find this rather time-consuming. However, I did solve the evil sudoku much faster than doing it my usual way.

[Lo2a]

Thnx alot, i used to think wen i solve sudoku but now, i won't

[maddy_no11]

thanx a lot...I always solved the easy ones pretty quickly but fumbled invariably over the tough ones.. This would help me a lot... Thank you very much

[ikenho]

very good i will trie to use this method in the future thanks!!!

[conductor_AJ]

And PENCIL erases off my nintendo, too.

[amcq]

The "first" step should be to scan the board looking for the OBVIOUS numbers that go in certain spots. For the example above, look in the left 3 quadrants. For the top-left, the number 6 is in the middle column. For the middle-left, the number 6 is in the right column. This means that for the bottom-left, the number 6 HAS to be in the left column. For that left column, the only possible locations are the 2nd and 3rd cells. You then scan both of those towards the right, and find that one of those rows has a number 6 already. This leaves only one cell for that number 6, the bottom-left cell. You can continue this logic for all columns and rows, and all numbers, to find numbers that can be immediately filled into the puzzle. After these are filled in, there's drastically less empty cells, and makes the process described above much faster.

[beelzebub123]

that is that exact technique on sudoku in brain age

[karmaghost]

actually, it's the reverse use of the tactic i use in brain age; i focus on one number at a time and place a small number in each box, rather than fill every single box with small numbers. Also, in brain age, you can't make any marks on the squares that already have numbers printed in them

[egonx]

http://angusj.com/sudoku/hints.php

[egonx]

... and "Naked Pairs, Triples & Quads", "Hidden Pairs, Triples & Quads", "X-Wing" and "Swordfish"

[egonx]

It's not always that easy. You'll need more elimination tactics then "Singles" and "Hidden Singles". Such as "Locked Candidates" (two kinds)

[ravi]

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