Frequently asked questions about Zugzwang.mobi

What is Zugzwang.mobi?: Zugzwang.mobi is a collection of chess challenges from recent games.
What is my task in each challenge?: Just find the best move. There is a unique solution for each position.
Why is the solution not always leading to a win?: Well, you cannot win from every position. The solution leads to a clearly better (or less worse) position than other moves. This may at times still be a miserable position, but in that case the alternatives would be dead lost.
Why does the solution not involve anything spectacular, like a sacrifice?: Because spectacular moves are not always best and best moves are not always spectacular.
Are solutions checked against endgame tablebases?: Where applicable, yes. However, humans do not play according to tablebases. Therefore, you may find moves that actually lose as a solution, based on the fact that they make the win considerably more difficult than all other moves.
Where is my account data stored?: You don't have an actual account. Instead, all data are stored in the 'local storage' of your browser.
How is my rating calculated?: Your expected score on any challenge is based on your current rating and the difficulty of the challenge (indicated by the number of stars). Based on the difference between the expected score and your actual result, a new rating is calculated. The calculation has been calibrated using a regression model for ratings of 2200 and above.
How was this collection created?: By analyzing TWIC files using various strong engines and automatically selecting suitable positions. There is no human prejudice in the selection process.
How frequently are new challenges added?: New challenges are taken from TWIC files and are usually added every Wednesday following a TWIC publication. But just follow us on Twitter to keep up to date.
I have a comment or suggestion, where can I send it?: Please send it to Wiebe Cnossen, the creator of Zugzwang.mobi.