Sudoku (9) Logic for Beginners
by
Don Harmon
Published by Another New Day
at Smashwords
Copyright 2011 Don Harmon
Smashwords Edition, License Notes
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Three Adjacent Square Identification
ACKNOWLEDGEMENTS
This book would not have been written except for my introduction to Sudoku by a very good friend and my buddy, Mr. Carl Zaby. Not only did he introduce me to Sudoku but he actually gave me help with some of the ideas contained here, which I desperately needed. Thank you, Carl.
I am also extremely grateful to a lovely couple in my home town who, when I let it be known that I was playing with Sudoku, pleasantly announced that they too enjoyed the challenge of Sudoku. I had already drafted some ideas toward this book. Then, low and behold, after I told them about what I was doing, I ask if they would entertain the possibility of looking over what I had written. “Sure” they said. What an eye opening experience. So, Tom and Tricia Hewitt, thank you, thank you, thank you for your powerful open & creative minds. It has been such a pleasure and I hope you recognize the incorporation of your helpful red lines. I could not have done it without you both.
SUDOKU (9) LOGIC - FOR BEGINNERS
FORWARD
This book contains no Sudoku puzzles.
Most books containing Sudoku puzzles identify the level of difficulty (at the top of the page) which is applicable to the puzzle presented on that page. Generally, there are 5 levels of difficulty; “Very Easy”, “Easy”, “Medium”, “Hard”, and “Very Hard”. This book presents “Logics” that will almost always allow you to solve “Very Easy”, “Easy” and “Medium” levels of Sudoku (9) puzzles. These logics may aid in solving portions of “Hard”, and “Very Hard” puzzles, however, to solve entire puzzles you will need these and additional complex logics. The logic concepts presented in this book are provided to let you, the reader, experience some of the “sequence of thought” which will lead you to solving entry levels of Sudoku (9) puzzles.
So, read, learn and apply those logics that are applicable to solving any “Very Easy”, “Easy” and “Medium” puzzles you encounter and you will move out of the BEGINNER classification.
NOTE
Other authors may use different terms and definitions to identify “Levels of Difficulty”, components, processes, logics, or strategies which I discuss here. Remember, a rose by any other name is still a rose. All I ask is that you understand the concepts presented here. I believe these concepts offer the most complete and understandable foundation of knowledge.
So, Here we go !!!!!!!!
This book establishes some SUDOKU (9) puzzle components, definitions, processes, logic and strategies for those who are beginning to solve entry level SUDOKU (9) puzzles. Usually there are 5 levels of difficulty, typically listed as:
1. Very Easy
2. Easy
3. Medium
4. Hard
5. Very Hard
As a beginner you should not expect to solve “Hard” or “Very Hard” Sudoku (9) puzzles and/or win Sudoku (9) competitions.
However, this book will provide most readers with sufficient knowledge of components,processes, logic and strategies to solve “Very Easy”, “Easy”, “Medium” and some “Hard” levels of Sudoku (9) puzzles. While these logics will allow you to solve the “Very Easy”, “Easy” and “Medium” levels, you will need these and additional complex logic to solve the “Hard” and “Very Hard” levels of Sudoku (9) puzzles. The advanced logic used to solve “Hard” and “Very Hard” Sudoku (9) puzzles are not included in this book.
Some puzzle books provide answers in the back of the book. Once you have selected a logic process and selected a digit for a specific square, it is O K to verify your selected digit ONLY.
Remember, it is up to you to select and apply the appropriate sequence of one or more logics that will lead you to a solution of any given Sudoku (9) puzzle.
The term “Sudoku (9) LOGIC ” is derived from the fact that a completed puzzle will contain:
9 squares in a horizontal row
9 horizontal rows
9 squares in a vertical column
9 vertical columns
9 squares x 9 squares = 9 = 81 squares total
9 boxes
9 unique digits (1 thru 9) in each horizontal row, each vertical column and each of the 9 squares in a box.
The 9 digits will almost always never be in sequence. There are some exceptions.
Sudoku (9) puzzle books may use numbers (digits), letters or symbols. The logics presented here apply to all three puzzle types (numbers, letters or symbols). This author has chosen to use the word “DIGIT” instead of the word “NUMBER”. The word digit specifies the numbers 0 thru 9. The digit 0 is not used in Sudoku (9) puzzles which leaves the digits 1,2,3,4,5,6,7,8,9.
The solving of one Sudoku (9) puzzle digit may very well aid in the solving the next Sudoku (9) puzzle digit, again & again & again. Be sure that the logic you select at any one time will provide you with only “ONE” possible digit solution. “NEVER GUESS”. Guessing may give you a whole set of wrong answers. You may not immediately see all of the logic sequences necessary to solve a puzzle at one sitting. Don’t give up. When you get stuck, take a break.
Only one of the 9 digits (1 thru 9) must be assigned (or preassigned) to each of the nine squares in a row, column or box. (This concept breaks into 3 rules).
SUDOKU RULES: (the challenge of playing SUDOKU)
RULE 1: Each of the 9 digits (1 thru 9) must be assigned or preassigned to each of the 9 squares in a horizontal row—(NO DUPLICATE DIGITS).
RULE 2: Each of the 9 digits (1 thru 9) must be assigned or preassigned to each of the 9 squares in a vertical column—(NO DUPLICATE DIGITS).
RULE 3: Each of the 9 digits (1 thru 9) must be assigned or preassigned to each of the 9 squares in a box—(NO DUPLICATE DIGITS).
UNIQUE LANGUAGE
The following content and presentation is the beginning of a unique method of communication relative to the transfer of Sudoku logic ideas with complete knowledge and understanding.
BOX IDENTIFICATION
Sudoku (9) puzzles, as described in this book, are made up of an “AREA” divided into 9 boxes. Each box is numbered 1 thru 9. These box numbers will not be shown in any puzzle book, but are used for purposes of illustration and information.
Each of the 9 boxes is further divided into 9 squares, making a total of 81 squares within a Sudoku (9) puzzle (area).
ROW & COLUMN IDENTIFICATION
Notice that the 81 squares are arranged into 9 horizontal rows and 9 vertical columns.
For purposes of illustration each row and column is identified as shown below. The
identification will be used in this book but not in other puzzle books.
HORIZONTAL ROWS are identified A thru I
VERTICAL COLUMNS are identified 1 thru 9
SQUARE IDENTIFICATION
In this book, the squares are identified by a combination of a row letter first and a column number second.
Examples: B5 - F3 - H7
THEREFORE:
B5 will always be located at the intersection of horizontal row B & vertical column 5 (in box 2).
F3 will always be located at the intersection of horizontal row F & vertical column 3 (in box 4).
H7 will always be located at the intersection of horizontal row H & vertical column 7 (in box 9).
Each identification will always locate a specific square within a specific box.
THREE ADJACENT SQUARE IDENTIFICATION
Three adjacent squares (in a box), horizontally or vertically, are identified by the horizontal row letter or vertical column number (first) and a box number (second).
Examples:
Horizontal row letter A + Box number 1 = A B1
Box number = B2
