Play
Against a person or against the machine. For a rating or for the pleasure of it. With a coach at your shoulder or with nobody watching at all.
Game modes
A real opponent and a real result. Every move is a transaction and the contract referees the whole game, so the rating it writes at the end is not an opinion.
Moves your Players rating. Analysis aids are switched off while the game is live.
The same online game with nothing on the line. Keep the evaluation bar and the best-move arrow switched on and treat it as a training game.
No rating change either way.
Ten opponents across nine engine levels, no hand-holding. The contract plays the machine's side move by move, so it referees a computer game exactly the way it referees a game against a person.
Moves your Bots rating. Both sides of the result are written on chain.
Pick a clock, press one button, and the seek pool pairs you with someone of roughly your strength. The band widens while you wait, and if nobody turns up it offers you the Challengers closest to your rating instead.
No empty lobby, no waiting on a stranger to notice you.
Tactics with the contract holding the answer. It hands out the position, checks the line you play, and settles the result, which makes a tactics rating that means something. There is an offline mode for pure practice.
Moves your Puzzles rating in Normal mode.
Move without hints, then get a straight answer about the move you played and the one the coach wanted. The machine waits until you have decided which to keep. Win a level and you win its badge.
Never affects any rating.
A quiet game that touches nothing. No network, no coaching, no rating, no record beyond your own device. For the aeroplane and the waiting room.
Never affects any rating.
One device, two people, one board between you. The game is saved to your history afterwards with the winning side recorded.
No rating change.
All nine hundred and sixty back-rank arrangements, properly generated and properly played. Opening theory will not save you here.
Available online and against the computer.
Set a position up, take moves back, push them forward, and let the engine argue with you. Any finished game turns into one with a single tap.
All aids available.
A rating is only worth having if it cannot be typed in. Your browser can be opened, read and edited by whoever is holding the device, so the browser is never allowed to decide a result. It only ever authors your own moves.
That is straightforward in a game against a person: the contract sees every move from both sides. Against the computer it works because the contract plays the machine's side itself, using the same deterministic search the app uses, seeded from chain data. Any node can replay the game and get the same reply, which is what makes the number defensible.
So Normal mode against a Challenger is rated, and it settles on chain the moment the game ends, however it ends: mate, resignation, timeout or draw. Learner and Offline are deliberately never rated, because in those modes you are allowed to take a move back.
The ladder
These are people, not notches on a difficulty slider. Each one is pinned to an engine level from 1 to 9, and each carries its own rating, which is why two of them share level 5 at different numbers: One-Eyed Pete throws everything at your king, Master Kaito refuses to be provoked, and they are exactly as strong as each other. More Challengers are on the way, and they will slot into the same nine levels.
You cannot walk straight up to the hardest thing in the app and farm a rating off it, and you cannot pad your number against the weakest either. The contract enforces a band around your Bots rating, so a rated game is always against something close enough to be a real test.
The Strength tab is still there if you would rather pick a level from 1 to 9 and ignore the personalities entirely.
L9
Bram has farmed the same field for sixty years and played chess on an upturned barrel the whole time. He cannot name a single opening and he will still squeeze your position flatter than a pressed flower. Every move looks like a happy accident. None of them are.
L8
Nobody knows Boxcar's real name, or why a man who plays like a former champion lives out of a shopping cart, and he is not saying. He settles on a milk crate and produces moves of unsettling brilliance between bites of your lunch.
L7
Nova does not get excited, tilt, or make interesting moves. Every decision runs through a mental pre-flight checklist. She will not dazzle you. She will quietly strap your position into a seat and lower it into the sun.
L6
Nana pours the tea, asks after your mother, insists you take another cookie, then forks your king and queen without changing her expression. Fifty years in the church-basement club left her a nasty tactical eye and no mercy at all. The cookies are a trap.
L5
Pete holds that every piece is expendable and defence is for cowards. He hurls knights and bishops at your king like cannonballs and either mates you by move 20 or scuttles his own ship trying. There is no third setting.
L5
Kaito is in no hurry. He will not attack you, dazzle you, or make a single move anyone would call fun. He builds a wall, absorbs everything, and waits for the endgame. Attacking him is like punching fog: exhausting, pointless, and somehow you end up on the floor.
L4
Jo is the opponent you learned on and never quite outgrew. She develops her pieces, castles on time and holds the centre. No tricks, no tantrums. Beating her feels earned, because it is.
L3
Deb does not take risks. Deb reconciles. She will trade the board down to a spotless symmetrical endgame and offer a draw with the enthusiasm of someone confirming a calendar invite. She simply declines to lose until boredom makes you do something silly.
L2
Dave learned chess at a barbecue in 2004 and has felt unbeatable ever since, a confidence entirely unsupported by the evidence. He trades to keep it simple, walks into the same trap cheerfully, and will absolutely tell you he let you win.
L1
The Professor has read every chess book ever printed and recalls precisely none of them when it counts. He will deliver a ten-minute lecture on the Sicilian and then hang his queen on move six. Never beaten a computer before? Start here.
The clock
Clocks are not run by your device and they are not run by ours. Each is projected from the chain's own record of when the last move landed, so there is nothing to argue about and no advantage in having the faster laptop.
Set the game up the way you like it, fast or slow, with an increment or without, when you create it in the lobby or when you press Quick match.
Bullet is where the architecture shows. A one-minute game needs a move to be final almost as soon as you let go of the piece, and the cluster settles a block in about a hundred milliseconds. Your move is validated, applied and recorded inside that window, and your opponent is pushed the new position off the back of the same block. No queue, no batching, no waiting for a confirmation depth.
The whole app is served by the nodes too. ITZA Chess is not a website somewhere with a chain attached at the side: the pages, the engine and the board all come off the same cluster that referees the game. There is no game server in the middle to fall over, get slow, or quietly decide something on your behalf.
Dave is waiting and he is not very good. Start there, or jump straight into the lobby and play a person.