#What HedgeHog is
HedgeHog is a backgammon engine built around neural networks. You can play against it, analyse your matches move by move, transcribe a live game and study positions, all in your browser.
The engine that plays and gives hints runs on your own device, compiled to WebAssembly. Nothing is sent anywhere for a game or a hint, it answers instantly, and it keeps working with no connection.
#Do I need an account?
No. Playing, hints, on-device analysis, Study and transcription drafts all work without one.
An account adds the parts that run on our hardware rather than yours: server analysis, the stronger models we do not publish for download, matches stored in the cloud rather than only in this browser, and live broadcasting. See Accounts and plans.
#Starting a game
Press New Match in the sidebar and choose between:
- Points match: a race to a set number of points, 1 to 99 and odd. The Crawford rule is applied automatically.
- Unlimited game: single games with no match score.
#Home
Signed in, HedgeHog opens on Home. Its top card is whatever you left unfinished:
- A match in progress shows its board, the score and whose turn it is. Resume match takes you straight back to it. A match lives in the browser it was played in, so another device shows no match to resume.
- No match in progress shows the opening position with a button for the length you last played, one-tap buttons for 1, 3, 5 and 7 points and money, and Custom for any other length, a clock or a coaching level.
New match on a match in progress asks before it ends that match, because an unfinished match is not saved.
Around it, Waiting for you lists analyses still running and transcriptions you have not finished, and Recent matches opens each saved match on its analysis. Your performance is your accuracy and XR over your last analysed matches. Your matches counts what you play by match length, with every match of 9 points or more together, and shows your largest blunder this week: the costliest decision of your own in a match saved in the last seven days, which opens the analysis on that move. It needs an analysed match to show one.
#Making a move
1. Roll. Press the Roll button, or the Space bar. 2. Move. Click a checker to move it with the first available die. You can also click the destination, or drag the checker there. 3. Confirm. Press Space again, or click the dice, to end your turn.
Undo takes back the last checker you moved, until you confirm the turn.
If you cannot use one die or either of them, the turn advances on its own with a "Forced" message.
#Bearing off
Once all 15 of your checkers are in your home board, the last six points, you can bear them off. Click a checker to take it off the board, or click the bearing-off tray to bear off greedily.
#Building on HedgeHog
The Community page documents the public WASM engine API, the downloadable models and the OGID position format: what you need to embed the engine in your own project, fine-tune from our published networks, or interoperate with other backgammon software.