Luck apart from skill
Every roll is rated: lucky, average or unlucky. You see whether a match was won by play or by the dice.
Intelligent Backgammon Factoranalysis —See exactly where you lose points
The Longgammon analyzer
The IBF neural engine rates every move and cube decision, computes your PR and shows the quality of play and the luck. Online — people and the AI, on dice you can verify.
4–3
Play this roll Click a checker, then a point. Double-click — the furthest move · you play White
Positions from «School of Play» by K. Nekrasov and N. Akhundov. Rated by the IBF engine two moves deep.
Every mistake, priced
Import a match, record a game played over the board or play people and the AI. IBF reviews every move and every cube decision.
Every play, ranked
Your move against the best: equity lost, the error class, the luck of the roll, win and mars chances for every candidate.
Double, take or pass
Cube decisions in match winning chances, with the score, Crawford and cube owner. The engine also sees when it is too late to double — «too good».
PR and luck for both players
Checker and cube PR, mistakes by class and, apart from them, luck: what the dice brought and how the match would end without it.
Your game over months
PR by match, where you lose most, mistakes by kind, luck against skill — across every reviewed match.
How it counts
One measure for every mistake
A mistake is the equity lost on a decision. PR is the average loss per decision × 500: the lower, the stronger the play.
- No error< 0.020
- Doubtful0.020
- Bad0.040
- Very bad0.080
- Blunder0.160+
- World champion< 2.5
- World class2.5–5
- Expert5–7.5
- Advanced7.5–12.5
- Intermediate12.5–17.5
- Casual17.5+
The confirmed PR counts online games only: the dice and the analysis are the server’s. Beside it — local and overall.
Play online — the review is ready at once
Friends, nickname search, an invitation to a match. The server rolls the dice and the app checks every roll. After the match — your rating and the full review.
A person or the AI
A friend from your list, a player by nickname or the AI on the server. The clock — fast, standard or long; before the start you see what is at stake.
A FIBS-style rating
Everyone starts at 1500, longer matches weigh more, your first matches move the rating faster. The AI and the robots share the table with you.
Dice you can verify
Before the first roll the server commits to a hash of its seed, the app adds its own. After the match the seed is revealed and the app recomputes every roll. Statistics audit the faces and the doubles.
Watch your friends play
The player decides who may watch: nobody, friends, everyone or by link. A delay in moves, the analysis of the moves shown. A game recorded over the board can be shown the same way.
Everything to improve, in one window
Positions to study
Save a position from a match or build your own — with the dice, the cube and the score. Up to 500 positions in your account.
Puzzle of the day
A book position checked by the engine. Only your first answer counts.
Odds calculator
How many of the 36 rolls take a point, with blocks and the head rule. The best point here — 30/36
Robots, the AI and people
The robots play offline too, the AI plays at full strength. Practice — analysis as you play, with take-backs.
Any match, reviewed
Import .mat and .lgm, or record a game played over the board: type the dice, click or drag the checkers.
A board to your taste
Five board themes and checker sets, your own colour for every part of the board, your own logo, light and dark app themes.
Every match at hand
A library with search, filters and your average PR. Online matches live in your account and open on any computer.
A guide inside F1
F1 on any screen opens its article: rules, PR, luck, the cube, the rating.
Who needs it
- Tournament players
Review your championship games and find the decisions that cost you the match.
- Coaches
Your students’ mistakes by class and each one’s PR, move by move. Watch their online games with the analysis.
- Tournament organisers
Record a game over the board and show it online: spectators see the moves with a delay, a fixed typo at once.
- Improving players
Play the AI and people, solve the daily puzzle and watch your PR go down.
The short answers
How do I get IBF?
IBF is in a private beta: access is by invitation. Write to us and we will send a link to the installer and a registration code.
Which game is IBF for?
Longgammon: long nardy with the doubling cube, the head and six-block rules, mars and Crawford. Classic long nardy without the cube comes later.
What is PR?
The average equity lost per decision, times 500. Only real decisions count: obvious moves and an obvious «no double» are left out. The lower the PR, the stronger the play. The confirmed PR counts online games only — their dice and analysis are the server’s.
How is luck measured?
Every roll is compared with all 36 possible ones: how much better or worse it is than the average for that position. The match total shows what the dice brought.
How do the dice work online?
The server rolls them. Before the first roll it sends a hash (SHA-256) of its seed, the app adds its own. After the match the server reveals the seed and the app recomputes every roll itself: the server cannot pick a roll for the position. A verified game carries the «Dice verified» badge.
How is the rating counted?
By the FIBS formula: everyone starts at 1500, longer matches weigh more, your first matches move it faster. Only rated online games change it — with people and with the bots on the server.
Who sees my game?
Nobody by default. Before the match you choose who may watch — friends, everyone or by link — the delay in moves and whether spectators see the analysis.
Do I need to be online?
For the analysis, the AI and online games, yes: the engine runs on our servers and improves without reinstalling. The robots play offline too.
Where are my matches stored?
Local ones stay on your computer and never go to the server. Online matches live in your account and open on any device; any of them can be saved to your computer as well.
Which files does IBF open?
Import of .mat and .lgm matches, export to .mat. A game played over the board can be recorded by hand.
Play your next match stronger
IBF is in a private beta: access is by invitation. Write to us — we will send a link to the installer and a registration code.
Already invited? Open the link from the message.Windows 10 and 11 · English and Russian