John C. Baumann

Sudoku Introduction

1. Each Sudoku puzzle usually can be solved by logic, and requires little or no mathematical talent. It is always presented in a partially completed form. (There are renegade puzzles which have no solution or require guessing for their solution.)

2. The Field is a square with 9 columns and 9 rows, subdivided into nine 3 x 3 squares or blocks. Each of the small squares are called cells. (slide 01 and 03)

3. The only rule: Enter digits 1 through 9 in the cells so a given digit ONLY appears once in each row, column, and block. (slide 05)

4. Basic solution technique 1: Hashing. Uses blocks either vertically or horizontally. When a digit appears in common rows or columns of two blocks, then the location of that digit in the third common block is limited to the other row or column. Sometimes the number cannot occupy one or more of these cells because the digit appears in another cell. (slide 07)

5. Basic solution technique 2: Counting/Entering Candidates. From the starting position, choose a cell then look in its row, column, and box to see what digits it can contain. Pencil the missing digit or digits (candidate) into the cell so you dont have to recount. As you solve cells, remember to erase candidates from other cells in the same row, column, and block. (slide 09)

6. When there is only one candidate for a cell, that cell is solved. (slide 11) When there are multiple candidates several logical techniques are documented on the internet. Some of the easier techniques are illustrated in slides 13 through 21. These should enable you to solve puzzles with ratings through hard. In the Williamson County Sun, a puzzle rated 4 or less rarely gets to the hard category. (at this writing, there are no even numbered slides. jcb)

Download and Install Simple Sudoku:

1. Open Internet Explorer (or, better yet, FireFox), then go to: http://angusj.com/sudoku/

2. Browse to "Download:" near bottom of page, left click on sudoku_setup.exe (811kb)

3. Click "Save", then on the next screen, click "Save". (I usually save the file, just in case something happens during installation. I may be able to correct a problem then start installing again without downloading...)

4. On the next screen, browse to the location where you keep downloads. Desktop is a good place, since it doesn't get lost - but you need to remember to delete the file after installation is complete, else your desktop gets pretty crowded!

5. Click "Save" and the file will download. Click Close when the download is complete.

6. While you are at it, save the two "Advanced Puzzle Packs" to the same location as the installation file. (These are puzzles which have instances of some advanced solving techniques on which you can sharpen your eye/mind...)

7. Minimize or close Internet Explorer, then navigate to the downloaded files. Click or double click on "sudoku_setup.exe" to install the program. I usually accept the defaults built into the install program. Click "Run", then "Next" or "Install" until you run out of screens.

8. When the program finishes installing, get a checkmark in Start Simple Sudoku, click finish and the program will open for the first time. You are ready to start using the program!

9. Minimize the puzzle page and go back and delete the install file. While you are at it, you can move the Advanced Puzzle Packs to the same folder in which the program is installed - or another folder under that program folder. Erase them from their original location after you copy them... (On my computer the program was installed in folder C:/Program files/Simple Sudoku, so I moved the puzzle packs to that directory. While I was in that directory, I created a desktop icon by right clicking on the file simplesudoku.exe and then moving to Send to: and left clicking the submenu item Desktop.)

Simple Sudoku Features:

(If you are the impatient type, skip down to 5. Solving Puzzles)

1. Information line at bottom of puzzle: displays status or error messages, the time the puzzle has been open (if selected), and an indication of the relative difficulty of the puzzle (if is generated by the program, not imported.)

2. Top line: Standard title, minimize and close buttons.

3. Second line down: Standard menu line. Many of the selections in the following two lines of icons are shortcuts to the entries in the drop down menus.

a. Help Menu: Good thing to have! Explains a little about the mechanics of using the program, and A LOT of good info on the logic of puzzle solutions. Page forward and back by clicking the >> and << boxes.

b. File Menu: here you can open or create a new puzzle, save a puzzle at any stage of its progress, restart a puzzle currently in progress, and print the current puzzle - so you can work on it with your pencil...

1) Most often used is "New". This generates a new puzzle after you have solved another. Note: the program remembers the difficulty level of the last puzzle you solved and opens another when the program opens.

2) Change difficulty levels by clicking File > Create New > Easy (or Hard or ...)

3) Input a puzzle manually - from the paper or magazine: File > Create New > Design. You can then click on a cell and enter the desired number on it. When you have entered all the numbers, check your work, then go to File > Start. (If you get a warning that the puzzle is asymmetrical, it may have multiple answers and requires guessing instead of just logic. I'd start over...)

c. Options Menu allows you to set your preferences on how the puzzle is displayed and how the program keeps you from making mistakes. You can resize the puzzle to fit your screen, show or hide candidates, choose candidate arrangement, and show or hide the timer (which runs whether it is shown or not...) Once you have set your preferences, you will rarely change them.

d. Edit Menu: the primary function is to allow you to exclude a candidate from the presently selected cell. The Undo and Redo selections allow you to change your mind about the last move you made. You may have to undo several items if they have been made using the multiple cell selection keys...

e. View Menu: Here are the assistance actions (some will call them cheating...)

1) You can get a hint from the program on the next move to make, you can tell the program to solve the next step for you.

2) You can mark cells with colors to help solving

3) You can "filter" the puzzle to show you only cells with a particular number in them. This helps solving A LOT. It will help train you to recognize patterns.

4. Icons third and fourth lines at top of puzzle:

a. Hover the arrow over an icon to get a brief description of its function. All these icons are repeats of items in the drop down menus above.

b. On the first line of icons, the ones I use most are the first to create a new puzzle the undo (counterclockwise arrow) and the hint (yellow button with )

c. The last line of icons are used to filter the puzzle to show only cells which have the same number in them. These are very helpful in seeing patterns. The last box with two dots in it filters the puzzle to highlight the cells with just two numbers (pairs) in them. The first, blank box is used to stop the highlighting of cells.

5. Solving Puzzles at last!

a. Bring up the program. If you want to change the puzzle to another difficulty level, open an existing puzzle, or load in a puzzle from the newspaper use the File > Create New menu.

b. Use the Options menu to set the assistance you want on the puzzle. I like showing candidates; if you do not show candidates you will only be able to enter a number in a blank cell. You cannot enter a candidate only.

c. Click on a cell to make it active, then enter a number. If you have error checking activated you will be told if the number is wrong. Double clicking on a cell will give you a menu from which you can select a number to be entered, a number to be excluded (erased from the candidates), highlight the cell with a color, remove the cell highlighting, or to undo the last entry. (This menu tells you the legal candidates)

d. Once the naked singles are determined and entered, then it is a matter of determining where numbers CANNOT be entered. If you were doing the puzzle with a pencil, you would erase a candidate from a cell with the program you EXCLUDE the number. When you have excluded enough numbers, then naked and hidden singles will appear and you can enter the correct number. You continue entering and excluding numbers until the puzzle is completed.

e. When a puzzle has a naked single, you can select View > Solve All Naked Singles. This will automatically enter the number at the naked singles spot, then search and enter numbers where other naked singles have appeared as a result of the last entry.

f. Most of the menu commands have icons or keyboard shortcuts. The keyboard shortcuts are shown to the right of the command in the menus. For instance, to solve all naked singles you would only need to tap the F12 key. To highlight all cells with 2 in them, click the square box with 2 in it.

g. Progress through the game (number of cells solved) is shown on the bottom line below the puzzle as well as error messages when you err. At the end of the game you will get a message about the number of hints you took and the number of wrong moves you made. Happiness is getting 0 and 0 in the hints and errors

Sudoku for Purists:

1. Some folks think that the person working the puzzle needs to do the candidate entering and erasing. You cannot do that with the Simple Sudoku program. You can, however, generate a puzzle, print it, then solve it with a pencil.

2. There are many programs on the net. Monday I entered sudoku in the Google search bar on my browser and the first selection is a pretty good one: websudoku.com

3. Note that, like most free sites, this one has a deluxe version you can buy.

4. Click the options button: Set Pencil marking which will allow you to enter up to 5 numbers in a cell. You will have to delete the numbers as you solve other cells.

5. Under options you can also choose a level of program checking of your entries with the how am I doing button.

6. Click Save options, then solve the puzzle by entering (or deleting) candidates. You can use the how am I doing button to check your progress it does not check your cell candidates.

7. At the main screen, you can select the puzzle difficulty easy, medium, hard, and EVIL!

8. If you like the program, put the URL in your favorites (bookmarks).