Sudoku

From Games

First, a question for you, dear reader: why have you come here? Have you never played Sudoku before? Do you want to learn more, and get better at solving Sudoku puzzles? Or a different reason?

Add Sudoku puzzles for others to solve, or add your own strategies.

Suggested puzzle source: [1]

For instructions, read Wikipedia's article on Sudoku

Contents 1 Terminology 2 Strategies 2.1 Basic patterns 2.2 Intermediate patterns 2.3 Advanced patterns 3 Extremely difficult puzzles 3.1 Puzzle 1 3.1.1 Easy 3.1.2 Very Hard

[edit] Terminology

Note: this article uses numerals to describe the symbols used in the puzzle, while writing out numbers used to denote actual quantities

• square = a place to put a number
• box = a 3x3 grid of squares

[edit] Strategies

I like playing Sudoku, but I'm not very deep into it yet, while I can partially recognize how deep it can go. I've used what I call search patterns, that is: searching for a few logical inductions which force me to place a specific number in a certain square. As I've played over the last few months, I've discovered new search patterns (wider, with an increasing steps of logic). I thought somebody else would've come up with names for different patterns, but I haven't found them, yet. Finally, the thought occurred to me that some of these unnamed search patterns are necessary for solving the highest difficultly puzzles (also, who, and how was it decided what the difficulty rating would be?).

Other thoughts: How does one make a puzzle (obviously, fill the grid with the row/column/box limitations, then remove a portion of the numbers, presumably while cross checking at various points to ensure no logical ambiguity)? Is a logical ambiguity (all squares filled except four, and only two pairs of numbers to fill them with) the result of a poorly designed puzzle, or an erroneous step during the solution?

[edit] Basic patterns

In easier puzzles, the first numbers I place are found by scanning rows (I don't scan columns as often as I could). I check the 1's in the first row of boxes. If two 1's are given, and the third row has two numbers given in the box which is missing a 1, or if some 1's can vertically eliminate the one or two blanks, then the answer becomes logically obvious. (do we need a picture, to make this description make sense?)

[edit] Intermediate patterns

Occasionally, in a certain box, an entire row or column of squares will be blank, while the other two rows or columns will be filled in. With the knowledge that three numbers MUST be in one particular row or column, you can sometimes narrow down the possible locations for one (or more) of those numbers in another box (sometimes narrowing it down to the logically necessary solution).

[edit] Advanced patterns

None yet identified.

[edit] Extremely difficult puzzles

[edit] Puzzle 1

[edit] Easy

6
			8	3	3	6
							8	7
	5		2				9
		9				8
					8		7
	9						1
			7		6		5
3					2

Fuck You................. Nice Game Though.............. Stoner's Rule!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[edit] Very Hard

			5
8		3
	2
			4				3	8
					2	4
		4		9
		5		6		2
					1	7
					8