Help, in plain words.

Two phones, each with CheckMates™ installed, and a flat table. One phone per player. During the beta both phones need to be iPhones (see below).

Open CheckMates on both phones and tap Play on each. The phones look for each other nearby. When one finds the other, it shows the other player's phone; one tap on either phone connects them.

The first time two phones pair, both show a short row of small pictures. Check they are the same pictures in the same order on both phones, then tap to confirm. That makes sure you joined the phone next to you, not one across the room. Phones that have played together before skip this step.

No Bluetooth, or it doesn't find the other phone? Tap Use a code instead and scan the code on the other phone with your camera.

Lay both phones flat, screens up, with their long edges touching, like two halves of a board. Each player sits behind their own phone. The app helps you line them up; if the phones get nudged during a game, it will ask you to line them up again rather than move the board on its own.

Only to find the other phone at your table and talk to it. It isn't used to locate you or anything else, and nothing is sent to us. See the privacy policy.

On iPhone: Settings → CheckMates Duo → Bluetooth, switch it on, then go back to the app. Also check Bluetooth itself is on in Control Center. Or skip Bluetooth and pair with a code instead.

• Make sure both phones have tapped Play and the app is open on the screen (not in the background).
• Check Bluetooth is on and allowed for CheckMates on both phones.
• Keep the phones within a metre or two of each other.
• Still stuck? Tap Use a code instead. On the same Wi-Fi, allow “Local Network” if your iPhone asks.

No. CheckMates draws the squares the same real size, in millimetres, on both phones, even when one phone is bigger than the other. The bigger phone simply has more room around the board.

The edges of the phones (and their cases) leave a small gap. CheckMates counts that gap as part of the board: the row of squares next to the gap is drawn a little shorter on each phone, so the grid lines up across it like one board.

Yes. Thick cases make the gap wider, and the alignment step takes it into account. Phones of very different thickness can sit at slightly different heights; a flat table helps.

Not yet. iPhone comes first. Android is planned after the iPhone launch.

Not yet. Mixing iPhone and Android is something we want, and we'll only say it works once we've tested it properly on real phones. For now, both players need an iPhone.

Standard chess rules, the same as any club: castling, en passant, promotion, check, checkmate, stalemate and draws.

No account, ever. Pairing nearby over Bluetooth doesn't need the internet. Pairing with a code may use the internet to introduce the two phones.

In TestFlight, take a screenshot in CheckMates and tap Share Beta Feedback, or open the TestFlight app and tap Send Beta Feedback. You can also email us.