SudokuME title

SudokuME is a Sudoku (or 'Su Doku') game for your Java-enabled phone or handheld device. Now you can fill up those idle moments on a train or at the airport with a challenging game of Sudoku - and all you need is a phone or similar device.

Unlike some mobile other Sudoku games, SudokuME provides a compact yet feature rich environment in which to tackle each puzzle. The ability to lock certain cells and to make note of your working out is provided via a simple yet effective interface. SudokuME will also automatically highlight duplicate cells, and check your solution to ensure it is correct. SudokuME also supports Sudoku games on either 9x9 or the more challenging 12x12 grids. You can also download ready-made puzzles from an archive straight onto your phone - or input your own puzzle (perhaps from your favourite newspaper?) You can also save numerous games onto your phone's persistent memory, and pick them up where you left off later.

In version 1.3 a timer has been added, to allow players to time how long they take to solve a given puzzle, and an undo feature is now supported, with the previous twenty changes recorded and capable of being re-wound.

The SudokuME MIDlet is Copyright S.E.Morris 2005.

Download SudokuME to your Java enabled phone from: (37k)

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What is Sudoku? | Keys | Tabs: (Load|New|Online) | Game Screen | Game Menus | Save Game Note | Online Sources

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What is Sudoku?

A Sudoku puzzle

Sudoku is an addictive number-based puzzle, rumoured to have originated in Japan. The rules are blissfully simple: Fill in the missing values such that each row, column, and 3x3 inner grid contains all the values, 1 to 9.

Take for example the cell marked with a red cross in the diagram. By a process of elimination, it is possible to deduce that this cell must hold the value 7.

This is how we might work it out...

The cell immediately to the right of our target cell can have the value 3 or 7. Now we have deduced our target cell is 7, we know the rightmost cell must be 3. And so the process continues, until we have correctly established the value of every empty cell.

And that's all there is to it!

The Keys

Keys guide

SudokuME is written in Java (Java2 Micro Edition), which allows it to run across a wide range of mobile devices without modification. The mobile market is populated by a huge number of different device models and types. Java smooths over the differences between devices by dictating that nine 'game' buttons must be available on all devices. It is up to the user (you!) to figure out how these 'game' keys map to the real buttons on your phone or handheld device.

On top of this Java allows access to the 'soft' buttons which are used as function keys by phones, typically tied to labels which may appear on the screen's footer. Java has less control over these keys, with the phone able to assign 'soft' buttons to actual physical keys as it sees fit. If a given phone has fewer physical buttons than required soft buttons, it will typically turn one of them into a menu key from where the 'missing' buttons can be selected (as menu items). Most phones have at least two soft buttons - this documentation is written with that assumption.

You may need to experiment a little when you first play SudokuME to discover how your phone's manufacturer has mapped Java's game keys to the physical buttons on your phone or handhelp device. (The configuration will be the same for all Java software running on your phone, so you may alternatively like to consult your device's manual or the online documentation of the manufacturer.)

One final note: although I have labeled the soft keys SOFT 1 and SOFT 2, they may not appear in that order on your given phone. (Indeed these are just convenient labels for function keys which may not even appear as physical buttons on your phone at all - although in most cases they will be.) Each manufacturer must determine how and where these 'soft' keys will appear.

The Main Screen

From here you can load and delete a saved game, create an empty grid to create your own game, or download game from online.

There are three tabs, which can be moved between using the SOFT 1 and SOFT 2 keys. Load shows a menu of games currently saved onto your phone. New shows a menu for creating new games from scratch (as well as an in-built example game). Online shows a list of games available over the Web.

NOTE: Moving to the Online tab will cause SudokuME to attempt to read data from the network. Your phone may display a warning about this.

The 'Load' Tab

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The Load tab allows you to load and delete saved games on your phone. Use the UP and DOWN keys to navigate through the list. If the list is bigger than the space on the screen, it will scroll accordingly. Naturally if you have not yet saved any games, the list will be empty. To select a game and have it load, simple press FIRE when highlighting the desired save game record.

Use the LEFT and RIGHT keys to flip between the various pieces of save game data. These are:

Record id and size are of use if your phone has only limited storage space available. To save space SudokuME compresses game data to reduce the number of bytes it takes to store. This enables the player to have many unfinished games on the go at once, without fear of filling up precious storage space on their phone. In the example screenshot, two games are displayed. The first has the identity number 4, and is 84 bytes in size. The second has an identity number of 3, and is 115 bytes.

To delete a record press the GAME A button while highlighting the desired save game record. A menu will appear, asking you to confirm your action. Use the UP and DOWN keys to navigate this menu, and the FIRE key to make your selection.


Upgrading from v1.2x to v1.3: version 1.3 will read save game records from 1.2x, so you can continue with your existing games after updating the application. However, the title and timer were not available prior to 1.3, and thus for old records the title will be set to "Untitled game" and the timer will begin at zero. (When 1.2x games are subsequently saved, they are written out in the new 1.3 format.)

The 'New' Tab

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The New tab allows you to create an empty grid. This is useful when copying a game from, perhaps, a newspaper or book of Sudoku puzzles. The third option allows you to play a test game. The test game is an in-built game which is useful for getting familiar with SudokuME's controls. (Perhaps in future this test game option will be replaced by an option to generate brand new Sudoku games?)

Use the UP and DOWN keys to navigate this menu, and the FIRE key to make your selection.

The 'Online' Tab

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The Online tab is used to download puzzles from an archive on the Web. When you access this tab, you may be prompted to grant permission for SudokuME to access the network. You will need to give this permission if you want to use this feature. Typically SudokuME downloads only small parcels of information, often less than 2k in size.

The online archive is divided up into two parts. Sudoku puzzles are gathered in collections known as 'bundles', while an available catalogue of all known bundles is available on the Web. When you first access the Online tab the catalogue will attempt to be loaded. And once successfully loaded, is displayed.

In version 1.3 of SudokuME the catalogue has been adapted to have multiple directories - the previous version's flat list would have eventually grown too long and cumbersome to use. Directories are signified by two 'greater than' / 'less than' symbols around their name (see diagram).

In the three diagrams we see a progression from the top level down towards a specific bundle. The first diagram shows two directories, "Daily Telegraph" and "SudokuME". Having selected the first, a list of bundles is display, as per the second diagram. Having selected the first bundle (containing nine games) the list of games inside that bundle is shown, as demonstrated in diagram three.

Navigation is done using the UP and DOWN keys, while the FIRE key makes your selection. Selecting a bundle (diagram two) will cause further network activity while the bundle loads. Once loaded, the bundle's contents will be available for selection (diagram three).

SudokuME will retain in memory the catalogue and bundle you have selected, unless you quit or pause the SudokuME application (for example, to receive an incoming call). Hopefully this will further reduce the amount of loading across the Internet your phone will need to do.

You may use the GAME A key to retreat from any level of this list back up to the previous level.

See the section Online Game Sources for more information on the titles of the various games, and where they originate.

The Game Screen

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Playing the game is as simple as navigating around the grid using the UP, DOWN, LEFT and RIGHT keys, while toggling the value in a given cell using the FIRE key.

If you should happen to put a value in a cell which is invalid, due to it being repeated on the current column, row or the inner grid, SudokuME will highlight in red all other 'offending' cells for the current cell only.

Screenshot 9

It is often handy to keep track of your 'working out' - possible values which you consider are suitable candidates for a given cell. Players using a 'hardcopy' Sudoku game (for example, from a book or newspaper) often pencil in their working out as small numbers into a given cell. This isn't really possible with SudokuME - for one thing, the display size on mobile devices is far too small to show tiny working out numbers.

As an alternative, pressing the GAME B key allows you to toggle between the main grid and a separate working out area below. Using the LEFT and RIGHT keys, along with FIRE, you can toggle on or off a given value in the working out selection.

Only the working out for the current highlighted cell is shown. A small dot 'marker' is placed onto the main grid as a hint as to which cells contain working out and which do not.

(See elsewhere for details of how using the working out feature impacts on the size of save game records.)

The GAME C key allows you to toggle the lock on and off for the current hightlighted cell. A locked cell appears in a darker shade (bold) and cannot be changed. Use this feature to highlight cells which were filled out at the start of the puzzle - or to secure from accidental change cells which you are confident are correct .

The GAME D key acts as a SHIFT key (like on a computer keyboard). Holding it down while pressing one of the other keys gives access to extra features. In the list below they are given as GAME D+???, where ??? represents the other key. Because phone keypads can sometimes be awkward to use, a banner sporting the legend << SHIFT >> appears below the grid while the GAME D key is held.

The GAME D+B key displays the game timer. (The timer is also accessible via the About menu. See later for details).

The GAME D+C key will perform an undo function. SudokuME will store up to twenty of the previous changes to the grid values (but not the working out or locks) and can reverse these changes with repeated presses of this key.

Here's a list of keys and what they do:

The Game Screen Menus

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The game screen menu allow access to a range of useful tools and facilities. To bring up this menu, use the SOFT 2 key.

Of particular note here are the About, Working and Solved? menu options.

About provides information, help and allows the current game to be re-titled. On the opening page the current game title and current timer are shown. SOFT 1 can be used to exit back to the game, while SOFT 2 will cycle to the next help page. Each help page shows the keys used in a given part of SudokuME, and their function. The GAME A key will bring up a page where the current game can be re-titled. (Handy for assigning a name to an old v1.2x game, perhaps?) The title can have a maximum of twenty characters.

Working provides an easy way to remove working out for cells which contain values. This can be done either for cells which are locked, or for all cells with values. Cells which do not have values (are still empty) are left intact.

The Solved? option checks the entire grid looking for duplicates, and marks them in red. This is a handy feature for when you have completed a Sudoku puzzle, and want to check if your solution is correct. Instead of moving the cursor over each cell in turn, looking for duplicates highlighted in red, simply use the Solved? option and any duplicates anywhere on the grid will be highlighted. (If nothing is highlighted, then congratulations - you have solved your puzzle!)

A Note on Save Game Records

SudokuME attempts to compress (using a scheme known as Run Length Encoding) as much data in the online bundles and save game records as possible. This reduces their size and thereby makes them smaller to store (save game) and quicker to load across a network (online).

The working out feature of SudokuME is very useful - but it requires a large body of data to function. It is recommended therefore that users clean up working out data once it is no longer needed (for example, because you have now determined the value of the cell to which it it associated) so that the RLE compression software can better reduce the size of your save games.

To help you do this, a handy Working option has been added to the main game menu.

Online Game Sources

The games available online currently fall into the following categories: