What's New in SudoKoach™

Note: Each version includes all of the features of the earlier versions.
If you are upgrading from version 2.0 or earlier, read these notes about how to upgrade to the current version.

What's New in SudoKoach 2.5a

Eight new strategies were implemented: BUG (Bi-value Universal Grave), W-wing (type 1, 2, 3, and 4), Finned X-wing, Sashimi Finned X-wing, and Turbot Fish.
I have clarified the descriptions in many of the big hints to make them easier to understand.
You can now enter puzzles from the keyboard in addition to using the mouse (thanks to Andrew Stuart, author of the outstanding web page SudokuWiki.org.)

What's New in SudoKoach 2.4

A fix for the online update that broke when I moved my website to a new provider. If you have version 2.0, 2.1, or 2.3, read this to see h ow you can get a copy of the updated program.

What's New in SudoKoach 2.3

The elapsed time counter is paused when SudoKoach is minimized.
You can now choose to have a big X drawn through cells with no remaining possibilities.
When opening a saved puzzle, the timer now continues from where it was when the puzzle was saved.
You can now shut off the annoying error message generated when international keyboards are being used.
The box that appears for little and medium hints now has a button you can click to get an explanation of the strategy involved.
The strategies in the Practice drop-down list can now be ordered by difficulty rather than alphabetically.
You can now display the answers to the current puzzle without having to print them.

What's New in SudoKoach 2.2

You can now highlight cells based on the number of possibilities they contain.
Coloring, a powerful technique for finding moves, is now provided.
You can draw lines on the board to help you find chains in the puzzle.
Eight new solving strategies have been added.
New options are provided for solving (the boring) naked singles.
Printing of puzzles has been improved, with a new option for printing full size.
And more!

What's New in SudoKoach 2.1

You can now print puzzles in black and white (and save your expensive color ink)
SudoKoach is updated for use with Windows Vista.
(Version 2.1b) Fixed a problem that prevented the creation of Superhuman puzzles..

What's New in SudoKoach 2.0

There is a new button window with buttons for commonly-used functions.
You can now make the possibilities you've deleted visible, and undelete them.
You can make Naked Singles highlighted on the board.
You can customize the colors used by SudoKoach to your liking.
You can specify that cells you've solved be shown in a different color than cells whose answers were given.
You can specify that the answers in solved cells be hidden.
Some big hints are enhanced with additional coloring.
Values that have been completely solved are now skipped in highlighting sequences.

What's New in SudoKoach 1.3

Starting with Version 1.3a, the online Help is available as a PDF file that you can download and print.
Version 1.3a corrects the description of the frequency of the Singles Chain and Singles Chain Contradiction strategies.
The big hint dialog now has a button you can click to get an explanation of the strategy used in the hint.
You now have more options for highlighting cells that contain certain possibilities.
When moving from one highlighting state to the next, you can choose to skip states in which no cells are highlighted.
You can now print the answers to the current puzzle.
A new strategy has been added: Rectangle Elimination. This strategy occurs frequently, and is fairly easy to learn.
A new strategy has been added: Unique Rectangles type 3.
If you make a mistake while entering a puzzle from a book or newspaper, you can now fix it by right-clicking the erroneous cell.
You can now get a list of the strategies needed to solve the current puzzle.
The practice menu now has a keyboard accelerator to allow you to quickly generate another practice puzzle for the same strategy you last practiced.
The Create new puzzle menu also has a keyboard accelerator which automatically creates another puzzle of the same difficulty you last chose.

What's New in SudoKoach 1.2

There is a new "practice mode" that helps you learn the strategies for solving Sudoku puzzles. Choose the strategy you want to practice and SudoKoach will create a puzzle for you that uses that strategy as the next step.
A new strategy has been added: Weak Singles Chain Contradiction.
The puzzle difficulty ratings have been changed slightly to make the increases in difficulty from level to level more consistent.
You can now restart a puzzle, either to try solving it differently, or to let someone else solve it.
The Help file now has frequency information on each of the solving strategies. This is helpful when deciding which new strategy you'd like to master.

What's New in SudoKoach 1.1

The help file is now complete, and includes descriptions of all the Sudoku solving strategies implemented in SudoKoach.
The menu clutter is reduced by consolidating several menu entries.
There is a new Undo until OK feature that undoes as many moves as necessary to eliminate all errors that have been made.
When you save a puzzle, all of the moves you have made are now saved. When you continue to work on that puzzle later, you can undo these move if you wish.
You can now create "superhuman" puzzles.
You now get congratulated when you finish a puzzle.
You are now asked if you want to save a puzzle when you quit before finishing.
The big hint dialog is now a more appropriate size.
The logic behind a couple of strategies was improved to catch all cases of them.
And more!

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