Questions and answers

About the app

What is DuelBox?
Thirteen two-player games in one app: Sea Battle, Backgammon, Tic-Tac-Toe, Four in a Row, Dots and Boxes, Ludo, Word Duel, Checkers, Blackjack, Darts, Archery, Pig and Puck Duel. Each can be played against the computer, with a friend on one phone, and with a friend on a second phone.

Are there ads or purchases?
No. The app has no advertising and no in-app purchases, and there is no account to create.

Which phones does it run on?
Android 12 or later, on phones and tablets. The app turns with the device and uses the width of a tablet or of a phone held sideways.

Does it need the internet?
Only for online play. Playing the computer, passing one phone back and forth and playing on two phones nearby all work with no connection at all.

Can I play alone?
Yes. Every game has a computer opponent at three levels, Easy, Medium and Hard. Set the level under Settings → Computer opponent.

Can more than two people play?
Ludo can be played by four on one phone. Seats without a person are played by the computer, so two of you can share the phone against two bots. The other games are for two.

In which languages is the app?
Eleven: English, German, Spanish, Turkish, Portuguese for Brazil and for Portugal, Arabic, Hindi, Simplified Chinese, Japanese and Korean. Change it under Settings → Language.

Is there a dark mode?
Yes, and nine more looks besides the light one, among them a high-contrast theme and a true-black one for OLED screens.

Can it be used with a screen reader, or without dragging and flicking?
Yes to both. The boards are read out square by square, and the games of skill can be played with on-screen buttons.

Playing with someone else

How do two of us play on one phone?
Open a game and tap Pass and play. In Sea Battle, Word Duel and Blackjack the phone covers the board between turns, so neither of you sees what the other is hiding. Puck Duel is played by both at once, one at each end.

How do we play on two phones?
Both need the app. One opens a game and taps Two devices; the other taps Home → Join a game → Search. Keep the phones close together.

How do we play when we are not in the same place?
With Online. One of you taps Create a code and sends the six-character code; the other enters it under Home → Join a game → Play online.

Which games can be played online?
All except Puck Duel, which is played in real time. Online play is marked Beta.

Can I play online against someone I do not know?
Yes. Open a room puts your game on a list of open rooms, and anyone looking at that list can join it. They do not see the name you set in the app, and you do not see theirs: each of you is “Opponent” to the other. Only a friend who types your code sees your name.

Is there a chat?
No. The other player sees your moves, and your name if they joined with your code. Nothing else.

The phones do not find each other.
Check that Bluetooth is on in both phones and that the app was allowed to find nearby devices. On some Android versions location has to be switched on as well; the app says so and offers the switch. Wi-Fi is not required, but it makes the link faster and steadier. Then keep the phones close together and tap Search again.

It says the other device is running a different version.
Update the app on both phones. Two different versions refuse to start a match so that neither shows a board the other cannot follow.

What happens if the connection drops in the middle of a match?
The match pauses and the board says why. When the phones find each other again, play carries on from the same position. Nobody forfeits for walking out of range.

The other player has to leave. Is the match lost?
A match on two phones cannot be put away for another day. A match on one phone can: leave it, and it waits under Continue playing.

Matches and records

I closed the app in the middle of a match.
A match against the computer or passed between two players is saved as you play. Open Home and tap it under Continue playing.

How do I delete a saved match?
On Home, swipe it to the left or right and confirm.

Why did starting a new game ask about my saved one?
Each game keeps one saved match. A new match of the same game on this phone would take its place, so the app asks first.

Can I take a move back?
In a match on this phone, Undo move in the bar takes back your last move where the game allows it. A dart, an arrow or a shot at the enemy fleet cannot be taken back.

Where are the rules?
Under How to play: at the bottom of each game's page, and behind the ? in the bar of every match.

How are my wins counted?
Every finished match is counted, by game and by opponent: each level of the computer, a friend on this phone, and another device.

How do I start my statistics again?
Home → Statistics → the bin at the top right. This deletes every record and cannot be undone. Your settings are kept.

The computer is too strong, or too weak.
Change Settings → Computer opponent. Hard plays Tic-Tac-Toe and Pig perfectly, so a draw at the first and an even record at the second are as good as it gets.

Single games

Why does Word Duel not take my word?
Words are 3 to 12 letters, or exactly the length chosen under Word length, and are spelled with A to Z only. Accented letters and other alphabets are left out.

Checkers does not let me make the move I want.
The game is international draughts on a ten-by-ten board. Taking is compulsory, and of all the captures on the board only the longest may be played. The board offers exactly the pieces and squares that are allowed.

Why is there no betting in Blackjack?
It is a duel between two players for rounds, not a casino game. There is no dealer and no stake.

My darts keep falling short or flying high.
Open Darts → Practice → Measure my flick, and the game takes your natural flick as the clean throw. Or set Aim control to Buttons and throw with a button instead.

I cannot hold the draw steady in Archery.
Set Your hand to Steady, touch with a second finger to hold your breath, or set Aim control to Buttons. The practice range has a lesson on each step.

Why do Darts, Archery and Puck Duel not turn when I turn the phone?
They are played along the length of the screen: a throw up at a target, and a rink with a goal at each end. The other games turn.

Data and privacy

Do I need an account?
No. There is nothing to sign up for. Online play signs the app in anonymously, with no name, email or password.

What does the app send?
Nothing you type, name or play is sent to the developer. A match on two phones exchanges your name and your moves with the other phone only. An online match carries them through Google's Firebase servers and deletes the room when the match ends. If you agreed when the app first asked, it also reports usage statistics to Google Analytics for Firebase, and a crash report to Firebase Crashlytics if it crashes. You can change that under Settings → Share usage data. The full policy is under Settings → Privacy policy.

Will my records survive a new phone?
If Android's backup is switched on, your saved matches, settings and records are part of your phone's backup to your own Google account, and come back when you set up the new phone. That is done by Android, not by the app.

How do I delete everything?
Uninstalling the app removes its data from the phone. To keep the app and delete only your records, use the bin on the Statistics page.