BG Analyst — Backgammon Position Analyzer

There is no XG API. eXtreme Gammon (XG) is proprietary closed-source software with no public API and no server integration capability. This tool uses Claude AI (Anthropic's large language model with vision) to analyse board positions from photos. The analysis is AI-driven pattern recognition and positional reasoning — not a rollout engine.

Key limitation: Claude is not a dedicated backgammon engine. Equity figures, win percentages, and move rankings are informed estimates based on training on backgammon literature, tournament records, and strategy resources — not Monte Carlo rollouts with millions of games. Treat output as high-quality coaching commentary, not engine-grade precision. Equity figures may differ from true XG values.

What Claude actually does

Uses its vision capability to read checker positions on all 24 points, the bar, and bearoff tray from your photo
Infers (or uses your specified) dice roll, cube value, player direction, and match context
Enumerates legal moves for the roll and ranks them by positional evaluation
Produces equity estimates using learned heuristics: pip count, anchor quality, blot exposure, timing, priming, race vs contact
Applies match equity table adjustments (gammon price, Crawford rule) when match score is provided
Provides cube theory analysis (doubling window, take/pass points)

True XG-equivalent open-source software

For rollout-based analysis equivalent to XG, these tools use neural-net engines that you install locally or on a server:

Software	Cost	Notes
GNU Backgammon	Free / open source	The closest free equivalent to XG. Neural-net engine with full rollout capability. Runs on Windows, Mac, Linux. Command-line scriptable — can be driven from a server.
BGBlitz	~€40 one-time	Strong neural-net engine. Cross-platform, offline. No subscription.
eXtreme Gammon 2	~$70 one-time	Industry standard for serious players. Windows only. No API — cannot be integrated programmatically.
Snowie	Commercial	Well-regarded older engine. Has analysis export features.

How to build a real server-based pipeline

Install GNU Backgammon (gnubg) on a Linux server — free, scriptable
Use Claude (or another vision model) to read the board photo and output a position ID string in GNUBG format
Pass that position ID to gnubg via command line or Python bindings to run rollouts
Return the rollout equity and move ranking JSON to the frontend

This app could be extended to do exactly that — Claude handles the hard part (reading the photo), GNUBG handles the hard part (precise equity calculation). The two complement each other well.

Error thresholds used in this app

Best — equity diff < 0.020 · shown in black
Error — equity diff ≥ 0.020 · shown in green
Blunder — equity diff ≥ 0.080 · shown in red

BG Analyst

Position Analyser

Board Photo

Drop board photo here

or click to browse · JPG, PNG, WEBP

Match Context & Position Details

Whose Turn

Bottom Home Board

Dice Roll

Cube Value

Cube Owner

Match Length

Score — Bottom (me)

Score — Top (opp)

↑ Edit any field above and click Analyse again to re-run with new values

Analysing board position… Reading checkers · enumerating legal moves · estimating equities

Analysis failed

Unable to process the image. Please try a clearer photo of the board.

Analysis Results

On move —

Roll —

Pip (mover) —

Pip (opp) —

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Candidate Moves —

#	Move	Equity	Diff	Win%	W-Gmn%	L-Gmn%	BG%	Rating

Cube Analysis

Position Notes

Confidence

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