ChessFlex: Play, Watch, Train

Chess that teaches while you play.

Play six bots, from Pawn (400) to King (2500), a friend on this phone, or anyone online. Your ELO starts at 1200 and moves with every rated game, with a graph of how you're doing. Untimed games, or real clocks from Blitz to Classical with increments and the move-40 bonus.

The bots play like people at their level: the lower tiers use neural networks trained on millions of human games, so they make the moves real players make, mistakes included. The King plays at full strength.

STUDY — free for 7 days, then one purchase, yours for good
• Coach this game: open a finished game and tap "coach this game". The Coach replays it move by move, points out the move that mattered and the better one, and sums the game up at the end, in English or 19 more languages (below). Share the summary as a card with the final board.
• Follow a live game: top tournaments move by move, with the coach's three best moves as arrows, commentary and Ask the Coach on the same board. Or study every world championship match since 1886, a move at a time, and guess each move before it's played.
• Learn an opening: pick from the classics and watch the bots play its main line while the coach explains the ideas, then play on.
• Watch bots play, narrated by seven voices: the Coach, a Commentator, a Cricket coach, a Radio host, an Auctioneer, a Nature documentary narrator, and the Bard, who tells each game as a war between two kingdoms (with a Persian Shatranj). The Coach and the Bard also speak Spanish, French, German, Portuguese, Dutch, Norwegian, Russian, Japanese, Korean, Mandarin, Hindi, Tamil, Telugu, Kannada, Malayalam, Marathi, Gujarati, Bengali and Urdu. Outside India, each language's Bard tells of a world of its own: castles and sierras, knights and forests, fjords and peaks, dunes and the sea, great rivers and the steppe, and in Japanese, Korean and Mandarin, tales of mountain and sea kingdoms. Pick a language, then a voice.
• The Study Coach in your own games: the best moves and why, with arrows on the board and the lines played forward.
• Ask the Coach: tap a question (the best move, the threat, was that move good, your plan, who's better) and the coach answers aloud.
• Learn mode: live win chances and the opening book as you play.
• Move-by-move analysis of every game you finish.
• Scan a position: pick a screenshot of a chess diagram and the board reads itself. Or paste any position (FEN) from a puzzle book or article, and practise it against the bots.
• Watched games are kept with the coach's commentary, to replay or share as PGN.

ChessFlex Daily: one puzzle a day, published as a QR code at chessflex.app. Scan it and solve it against the clock for a score out of 100 (speed and accuracy), keep your day streak, and watch your puzzle ELO move. Share a result card with the puzzle, no spoilers. Every Daily you've played is under Games › Puzzles.

Play anyone online: send an invite as a QR code or a link, to an Android phone or an iPhone; rated, with clocks or correspondence, draw offers and resign. No account: you play anonymously, under your handle.

Take back and play on: after a game against a bot, replay the position before your last move, or any move of the game, as practice against the same bot, with undo. Your rating never changes.

Free always: playing every bot, online games, ChessFlex Daily, ratings and the ELO graph, opening names, take back and play on.

Private by design: no account, no ads, no tracking. The engine, the bots, the coach and its voices all run on your phone, and your games and Daily results stay there. The Daily puzzles and live games are downloaded from chessflex.app, which receives nothing about you. Playing online is optional: invite anyone, anywhere, by QR code or link, and play anonymously under your nickname. Only those games go online, through Google Firebase, carrying a nickname and the moves, nothing that identifies you.