ZugZwang: Chess Screen Time

Your apps stay blocked. A solved chess puzzle opens one of them for five minutes.

ZugZwang turns the reflex of opening an app into a move you have to think about. Choose the apps that eat your day. They are blocked at once and stay blocked. When you open one, a chess board comes up over it with one way through: solve the puzzle.

HOW IT WORKS
• Pick the apps to block from the apps on your phone.
• Opening a blocked app brings up the board. Tap "Solve chess puzzle".
• Solve it and get five minutes of that app, or of your whole list if you prefer. When the time is up, the board comes back on its own.
• The first wrong move fails the puzzle. The solution then plays out on the board, and a failed puzzle never unlocks anything.

A RATING THAT IS YOURS
• Three puzzles during setup find your starting rating, from beginner to strong club player.
• Every puzzle after that moves it, like an Elo puzzle rating. Puzzles are served around your level, so they stay hard enough to make you stop and think.
• 20,000 rated puzzles: mates, tactics, endgames, promotions.
• Endless puzzles on the Puzzles tab, with filters for kind and length.
• A daily streak, your rating history, and one global leaderboard.

STRICT MODE
With strict mode on, removing an app from the list or turning strict mode off needs a harder puzzle or a 24-hour wait. Adding to the list is always allowed.

THE ACCESSIBILITY SERVICE
ZugZwang uses Android's AccessibilityService API for one thing: to learn which app came to the front, so the board can come up over an app on your list. It cannot read what is on your screen or what you type, and it keeps nothing and sends nothing. It is off until you turn it on in Settings; the app explains what it does and asks for your agreement before sending you there. You can turn it off at any time in Settings › Accessibility, and while it is off nothing is blocked.

YOUR PHONE STAYS YOURS
• You can always turn blocking off.
• Your rating and progress are saved to your account (sign in with Google), so they move with you to a new phone, an iPhone included.
• Which apps you block stays on this phone.
• No ads.

SUBSCRIPTION
ZugZwang Pro unlocks the whole app. Choose a monthly or a yearly subscription. The yearly plan starts with a 7-day free trial, and if you allow notifications you get a reminder two days before it ends. Payment is charged to your Google Play account when the free trial ends, or when you confirm the purchase. The subscription renews automatically until you cancel it, which you can do at any time in Google Play under Payments & subscriptions.

Terms of Use: https://use-less.app/zugzwang/terms
Privacy Policy: https://use-less.app/zugzwang/privacy

Puzzles come from the Lichess open puzzle database (CC0).

Recent changes:
Stop halfway through setup and pick it up right where you left off. Your apps stay open until your plan starts, so an unfinished setup never locks your phone. Reminders can be turned on right after you pick your piece. Offers now show how long they last. Picking your piece and colour works smoothly again, and the bar at the bottom of the screen matches every page.