Features
One engine shared by the browser and the chain, two boards, a coach, thirteen lessons, a full review after every game, and an app you can install. Here is the whole thing.
The engine
Most online chess has two chess engines: one in your browser to draw the board, and one on the server that has the final say. When they disagree, you lose the argument.
ITZA Chess has one. The rules live in a small, deterministic Rust core with no standard library. The contract links that core directly. Your browser runs the very same code compiled to WebAssembly. There is no second implementation to drift, so the board in front of you and the referee on the chain cannot disagree about what is legal.
It is checked the way chess engines are actually checked - by counting every legal position to a given depth from known test positions and comparing against the published totals, including 4,865,609 positions at depth five from the opening.
Because a move is sixteen bits, sending one as its own transaction is cheap enough to be the normal way to play - which is what makes the contract able to referee at all.
The board
The flat board is fast and familiar. The 3D board is a table you can walk around. Swap between them in the middle of a game and nothing is lost.
The staunton shapes everyone knows.
Cleaner silhouettes, heavier weight.
Bold letters in discs. Maximum readability.
Decorative medieval silhouettes.
Against the free tier everyone actually uses
So the fair comparison is not against a subscription. It is against what you get without one, and the tools that actually make you better are the ones kept behind the paywall everywhere else.
| Free, per day | The big sites | ITZA Chess |
|---|---|---|
| Game review | One free, rest paid | A free look daily, full review when you subscribe |
| Puzzles | A handful free | A daily allowance free, more when you subscribe |
| Playing chess | Free | Free, all time controls and all bots |
| Coaching while you play | Reacts to the move you played | Scores every legal move, before you commit |
| Lessons | Sampler, rest paid | All thirteen, free |
| Advertising | Yes, unless you pay | None, ever |
| Result you can verify | Trust the operator | Written by the contract |
Free-tier limits at other sites change from time to time; check theirs before taking ours as current. The row that does not change is the last one.
A result cannot be fabricated. The contract saw every move of the game and computed the rating itself, so there is no version of events that exists only on somebody's server. No centralised site can offer that, because on a centralised site the operator is always the last word.
It does not tell you whether a human chose the moves. Someone running an engine in another window is invisible to a contract, and anybody claiming a chain solves cheating is selling something. Fair-play enforcement is a hard problem everywhere: the big sites close six figures of accounts a year over it, titled players included.
What we do have is the timing of every move, recorded on chain by the referee rather than reported by the client - which is the strongest signal there is for telling a person from an engine.
Tactics and pairing
Two things most chess sites do on their own server, done on the chain instead.
The contract holds the position and the solution. It hands you the position, you play the line, and it checks the line and settles the result. Your tactics rating is therefore earned the same way your game rating is, which is not true anywhere else we know of.
Pick a clock and press one button. You go into a seek pool, the contract pairs you with someone near your rating, and the band widens as you wait rather than leaving you staring at an empty lobby.
Online play
Open games list the creator's name and rating, the time control and the tags on the game. Create one, join one, or cancel your own. Walk away mid-game and a resume pointer brings you back to it.
Clocks are projected from the chain's own record of when the last move landed, so both players see the same time. A fifteen-second grace after the flag means a dropped connection does not cost you the game outright.
Offer a draw, accept one, or resign. Claim a win on time once the flag has fallen and the grace has passed - and only then, and only if you are the one being kept waiting.
If your device and the chain ever disagree about the position, the client throws its copy away and replays the game from the chain's record. The chain is always the one telling the truth.
Talk to your opponent over the same encrypted messaging that powers ITZA Chat, with an unread badge and a notify sound. Only the current opponent's conversation appears, and the whole feature can be switched off.
All nine hundred and sixty starting positions, generated properly and played properly. Pick one, or let the game choose.
Afterwards
When a game ends the review is already waiting. Each move is graded from brilliant down to blunder, both sides get an accuracy score, and the move you should have played is there beside the one you did. Click any move to jump to that position, then keep playing from it on an analysis board.
Finished games are filed in History as cards, each with a picture of the final position, a won, lost or drew badge, the rating change, the opponent, the time control and the date. Open one to step through the whole game with the arrow keys, copy the PGN, or start a rematch.
A saved game is only coordinates and a little metadata, which is small enough to live on the chain under your own account. Sign in on another device and your games are already there. Local history keeps working with no connection at all - the chain layer syncs on top of it when there is one.
Analysis aids
The evaluation bar and the best-move arrow are genuinely useful, and genuinely unfair in a rated game. So they are gated.
This is enforced by the client and is part of what makes a rated result mean something.
Comfort
A chess app is a lot of small squares and small pieces. Several of the settings exist purely so that stops being a problem.
Everything you change is kept on the device and applied the next time you open the app.
Install
Installable on every platform that allows it, and fully playable when the network is not.
Runs standalone with no browser bar, on iPhone, iPad, Android and desktop.
Practice games, lessons, review and history all work with no signal at all.
Nothing to download, nothing to approve, nothing to update by hand.
Required for installation, and for the signing that happens underneath it.
Every feature on this page is live right now. Open the app and try the ones you care about.