Chess: hands, voice or VR

• Mouse or touch: tap one of your pieces, then a lit square; or drag the piece there. The board stays still; scroll to come closer.
• Your hands (a laptop with a camera): a ring follows your hand over the board. It aims from your knuckles, so closing your fingers doesn't nudge it, and it snaps to the squares that make sense: your pieces that can move, and, with a piece in hand, the squares it can go to. Pinch over a piece to lift it, carry it, and let go over a square; a quick pinch chooses a piece, and a second pinch on a square plays it. Pinch with both hands to zoom. If the board feels too big or too small for your reach, press Fit the board to your hand and pinch at two corners where it feels comfortable. If your hand slips out of view mid-move, the piece goes back. Turn on Look round with your head if you want the board to stay put behind the screen as you move.
• Your voice: press Talk to the board and say a move, like “knight to f3”, “e4”, “bishop takes c6”, “take the queen” or “castle kingside”; when only one knight can move, “knight” is enough. Or hold the space bar while you speak, for one move at a time. If Jarvis isn't sure he heard you right, he shows the move as a gold arrow and plays it a moment later unless you say “no” (“yes” plays it at once). You can also say new game, play as black, level club, take back, hint, analyse, back, forward, why, or quiet. If two pieces can make the move, Jarvis asks which.
• A cardboard viewer: look at a piece and tap the screen, or press the viewer's button, then look at a square and tap again. Holding your gaze on a square for a second works too. How to make a viewer.
• Your phone as the VR viewer: press Pair a phone on the laptop and scan the code with your phone (or type it in). The phone shows the same board in your cardboard viewer, live, while the laptop runs the game, so you can play with your hands or voice on the laptop and watch in VR, or choose squares with your gaze from inside the viewer. On Android, Chrome's menu offers Install app to keep it on your home screen.
• A VR headset (Quest, Vision Pro): the board appears on a table in front of you, 40 cm across. Point at a piece and hold the trigger, or pinch with your bare hands, to pick it up; let go over a square.

Jarvis and the analysis

After each of your moves, a second Stockfish grades it and Jarvis says so: the best move, a good one, or an inaccuracy, a mistake or a blunder, with the reason found on the board and the better move. Every few moves he offers a quote from a great player or a fact about the game. Why? asks the coach to explain the move in plain words, from the engine's facts only; anything it writes that the facts don't contain is cut.

Analyse (any time, or when the game ends) steps through the game with ◀ ▶ or the arrow keys: the bar shows who is better, the blue arrow is Stockfish's move, and every move gets its mark (!, ?!, ?, ??). Try other moves for either side, then Back to playing carries on from the position on the board.

Pawns promote to a queen unless you say otherwise. Listening only runs while Talk to the board is on: Chrome and Edge send what you say to their own speech service to turn it into words; other browsers record while you hold the button and send it to this site's transcriber. The opponent is Stockfish 19 running in your browser at the same four levels as Chess Ghosts. The camera, when you use it, is read in your browser and never leaves your computer; nothing about the game is sent anywhere.