Puzzle: is an exercise to be solved using 1 or more moves.

Series: is a consolidation of several exercises (often 10) completed one after the other, at the end of which a total score is calculated.

Tactics exercises work your mind and this is essential to sharpen the vision of the game. Practicing daily will allow you to quickly recognize the specific positions of the pieces which favor combinations and it will develop your strategist instincts. The "tactics practice" module takes place in a fun-filled world. The "mix" mode will work your memory. And the "battle" mode will offer you an opportunity to compete against opponents. A great way to spice up the exercises!

As for any new service the answer is yes. We will listen to your comments and suggestions and will do the improvements and modifications if necessary. This could particularly be the case related to the calculation mode of Elo for which taking a step back is necessary. Same for the proposed statistics.

With regard to puzzles, the database will grow over time.

Two Elos are calculated. One is "tactic" Elo and the other is "battle" Elo. They are calculated by using the Glicko system.

Tactic Elo: A tactic Elo is calculated after each exercise but only during the first round. If you redo the same exercise later on, it will not result in a change of Elo.

This calculation is done in practice mode and also in mix mode or battle mode.

The calculation is based on:

- the resolution time

- the number of errors

Each puzzle has been evaluated by us and has received an Elo. Just as how the Elo of a player is calculated against a real opponent, we evaluate the Elo of a player compared to the difficulty of the puzzle.

A win is calculated if the puzzle is solved within the reference time (maximum 30 seconds per move) and if no errors are committed.

A draw is calculated if the puzzle is solved within the reference time and that only one error is committed.

A defeat is calculated in all other cases (reference time exceeded and/or the number of errors are greater than 1).

Battle Elo: It is calculated after each battle, after comparing the scores of the two players. The highest score is awarded the win and the other the defeat. In case of equal scores, it is a draw.

A score is calculated after each puzzle and a total is calculated at the end of each series.

The score ranges from 0 to 100000 points for each puzzle.

It helps to evaluate your performance more accurately than a simple Elo calculation.

As the resolution time and the number of errors are taken into account, your score allows you to assess your progress, especially when you repeat the same series several times. In this case, when your score improves, you are notified at the end of each puzzle.

The practice mode is the standard round. Each series is classified in a tree of sections. You choose the section that you want to work with, the type of exercise that suits you and its difficulty.

Catogories: each category has an icon that sometimes describes the number of moves (x1, x2, x3, ...) and also the difficulty of the puzzles (shown with a green face (easy), orange (average), red (difficult). See the below example from the category of easy puzzles to solve in 3 moves.

"Mix mode" is a mode with random generation of puzzles. When generating a "mix", 10 puzzles are randomly selected from the entire database of puzzles while considering your account settings (Elo strength, already completed puzzles only, unsolved puzzles only, choice of section, etc.).

Since the type of exercises (checkmates, forks, enfilades, etc.) are mixed, it allows you to work your mind in a different way and to develop other reflexes

A "battle" is a game between two players. With a send/receive system of challenges to connect the players, they compete on 10 randomly selected puzzles across the entire database. This selection is made considering the strength of the two players.

The two players do not need to be available on the site at the same time to play the "battle". They take turns and the end result will be displayed when the two players have completed the round.

A "battle" Elo is calculated following each "battle" by comparing the scores of the two players to decide if it is a win, defeat, or a draw.

Competitions will be held at regular intervals on the site. Dates of upcoming tournaments will be posted in advance on the home page of the practice module.

Competitions are held on the day and the specific timeand have a limited time duration between 10 and 30 minutes.

It is necessary to register in advance. Once the tournament has started it will be too late.

At the end of the competition a ranking is given and the first 3 places are highlighted in the player statistics.

Unlike "battles" which use puzzles from the practice database, tournaments are played with new puzzles.

Indeed, the game interface is designed to fit mobile and tablet screens.

The "Quit" button at the bottom of the page and for mobile mode the icon allows you to quit the puzzle and move on to the next. If a puzzle is completed for the first time, a loss of Elo is calculated in case if abandoned.