Since 2002, the aptly-named 4Pockets.com has been creating applications and casual games for pocket PCs and smartphones, including Breakout clones, jigsaw puzzles, pinball games, and of course, sudoku. Their version of the ever-popular puzzle game has received a slight makeover and a cute Japanese doll-shaped mascot for its DSiWare release, but don't be fooled; Sudoku 4Pockets is intended for serious players.
The overall goal here is the same as every other sudoku game: to solve the puzzle by placing the numbers 1 through 9 into a grid so that the same number is not repeated in any row, column, or block - but that's about where the similarities end. After choosing your difficulty level (Beginner, Intermediate, or Advanced), Kiku the doll will let you know the exact difficulty via her little speech-bubble on the top screen, using sudoku-specific terms that the casual player will need to look up on their own; she will not explain them until you ask for a hint, nor are any definitions contained in the Help file. Here's a hint: naked singles' are cells containing only one possible candidate number, and hidden singles are cells with multiple candidate numbers but only one possible solution. She'll tell you how many of each solving technique are contained in each grid, which is nice, but without prior knowledge of what the terms mean, the information is useless.
To fill a cell with a solution, tap and hold your stylus on the screen to watch a small number menu pop up, then drag the stylus to your chosen number and release. Though there are number buttons in the bottom right-hand corner of the screen, those are used to highlight individual numbers on the grid as well as cells featuring that number as a candidate, helping them to stand out on the grid. “Candidates” are numbers that could possibly be used in any given cell in the grid, and in Sudoku 4Pockets, they are each denoted by a darkened square on a mini-grid within each cell. It's an interesting way of showing candidates, but players used to seeing numbers instead of dark and light squares will be thrown off at first. There is no Undo either, so if you solve the wrong cell on accident or take away the wrong candidate, you'll have to remember what you did and fix it yourself. You may revert the candidates to their original auto-filled values at any time, though this will undo all of your edited candidate values, so be careful.
In most of the other sudoku games on DSiWare (if not every other sudoku game), you're expected to fill in your own candidate numbers. In Sudoku 4Pockets, however, every single open cell is pre-populated with its available candidates. There is no way to turn this auto-completion off in the options, though you may turn their visibility off and on. When you enter a solution into a cell, any candidates for that number in that cell's block, row, and column will all automatically disappear, even if the solution you entered was incorrect. It is irritating to not be allowed to fill cells with candidates on your own at the outset, at least, and then perhaps choose later on if you like to have the game fill them in automatically (as in EA's Sudoku).
With the candidates constantly shifting, chances are you'll find yourself on the wrong path — and quickly — if you don't use the “Check” button after solving each cell. Kiku will pronounce the sudoku grid either valid or invalid, and since the game does not normally offer any way of discerning which cells were pre-solved and which you solved yourself, you'll have to toggle “Alert Wrong Entries” via the Options menu to find the incorrect solutions if you don't have a photographic memory. Even if you have it set to alert you, however, the candidates will still change on their own to reflect what numbers you've used to fill your cells, correct or not.
If ever you get stuck, tap the “Hint” button and Kiku will point out a cell using one of her solving techniques and give you the correct solution. It is possible to infer the meaning of the terms used in the game in this manner, but forcing you to use hints is not a good way of teaching how to play sudoku, especially when the game provides hints for each cell in order. If you choose to decline the hint by pressing X in hopes to have her explain a different move for you, the game will obstinately continue to provide the same hint until you've solved that particular cell either by filling it yourself or pressing Y. Bored to the point of tears? Tap “Solve” to have the game show you the completely solved grid. Your time is displayed on the top screen, along with how many hints you've used during a given puzzle. If you finish a grid, whether via using Y over and over or actually muddling through this needlessly confusing version of sudoku, you receive fireworks on the top screen while the game displays your statistics on the lower. Sudoku 4Pockets does not save your information for any kind of running total, though, so if you're into scores, record times, and knowing exactly how many of the 3,600 available puzzles you've managed to solve so far, you're out of luck.
Visually this game is simple and clean. Kiku herself is adorable, naturally, and the fonts and buttons are all easy to read. A loop of synthesized piano music plays in the background as you work your grid, soft and pleasant to the ear. The other clicks, chimes, and even the buzzer noise are also subtle, yet present. Sudoku 4Pockets is a very well-packaged title; it's a shame the gameplay is so flawed.
For a game marketing itself to sudoku players of all levels, Sudoku 4Pockets is remarkably user unfriendly. The candidate auto-filling will be a hassle for experienced players who enjoy methodically working their way through a grid without their annotations constantly shifting around them. Newbies to the game (and self-taught players as well) will be left dreadfully confused by the terms Kiku uses to describe solving techniques, especially with no explanations available in the Help file. The inability to differentiate user-input solutions from pre-solved cells as well as the lack of a proper Undo function only increases the overall hassle. There are better sudoku games in the DSi Shop at the moment, so unless you're an advanced player who doesn't like to fill in their own candidates and already knows what a "Swordfish" and an "X-wing" are, there's no need to kill yourself trying to wrap your head around this title.