The name Sudoku derives from the Japanese words that indicate each number can only be used once, which is the premise of Sudoku. You have a 9x9 grid, which is further divided into nine 3x3 blocks. Each row, column, and block must only contain the digits one through nine once. Typically a Sudoku puzzle reveals a few cells in the grid, and you must use logic to work out the rest.

For instance, if you know the position of eight of the same number you can work out the position of the ninth efficiently - because, of course, it can't be in the same row or column as any other. Thus there will be one single row and column intersection (or cell) that you can safely use. However, you'll never be given anything as easy as eight of the same number! So it would help if you progressively worked out the cells through deduction and reasoning, even the process of elimination.

Many strategies abound. And, there's always brute force reasoning where you figure out every possible number that could go into every possible cell and then eliminate options as you fill in cells. Of course, on a pen-and-paper version of Sudoku you'll run out of room and you'll ruin your paper with scribble. Here comes Gamovation's free Sudoku Club app - available on the Google Store: Sudoku Android and the Apple Store: Sudoku iOS where you can make as many notes as you want, and work through thousands upon thousands of free puzzles at all ranges of difficulty.

With Gamovation's Sudoku Club, you get a highly polished, very accessible, and delightfully aesthetic rendition of Sudoku to test yourself and improve your logic and thinking skills. The game will keep track of your progress and provide you a raft of options to add notes, fill cells in with numbers, erase them, verify your accuracy, get hints, monitor your mistakes and historical progress - and, if you like, buy extra hints too, with in-game currency.

The game is free to download and play and you don't need to spend any real money at all. It's ad-supported but you can choose to pay a small in-app purchase to remove ads, as well as choose to purchase coins for hints. However, you can also get daily gifts for free, and you can join a Sudoku club for free and meet and make new friends who also love brain-training games.

The game will collect your stats for you to challenge yourself against and improve, or even to see how you rank against other players worldwide.

You can also make the game more challenging if you like by adding a timer and limiting the number of mistakes you're allowed to make.

Gamovation has put a lot of thought into the user interface, giving it many features that competing Sudoku titles don't offer. For example, you can have numbers removed from all your notes when placed in a cell, highlight the entire block/column/row for selected cells, or hide numbers that have already been placed in all nine cells, as well as other nice simple quality-of-life features that help you focus on the challenge and avoid misclicks and other mistakes.

If you have played Sudoku previously you know it's a brilliantly simple brain-trainer and thinking game, and Gamovation's Sudoku Club really sets a new standard for electronic, smartphone Sudoku games. It's a must-have; you can't go wrong for the price, and it brings value and quality way beyond what you would expect for a free game. With new puzzles every day, there's always a new challenge.

Check out the trailer below, and download the game today: