New Tool: ChessDB Explorer

ChessDB is a long running and genuinely impressive project: a large, position focused chess knowledge database that exposes its analysis through a web interface and a FREE public API. Given a position, ChessDB returns a structured view of what it knows about that position, centred on ranked candidate moves, scores, win rates and explanatory notes.

I was asked by Bojun Guo to build a dedicated web application for ChessDB and to host it as part of my own platform at chessboardmagic.com. The original ChessDB interface already does the hard part extremely well: you give it a FEN and it gives you serious data back, quickly, however, this was built as a sample application for what could be done, not a showcase application.

Starting from that solid foundation, I built an initial version of the ChessDB Explorer (more updates are incoming), hosted at chessboardmagic.com, with the goal of making ChessDB easier to explore while working through real games, positions and ideas.

TL;DR – Try the free ChessDB Explorer here:
http://chessboardmagic.com/chessdb
No signup required. See what your positions really look like through ChessDB's database.

Features and Functionality

Below is a practical overview of what ChessDB Explorer supports today.

1. Create new analysis, or load games

You can start a fresh analysis from scratch, or load games into the platform and explore them position by position. Games can be imported from Chess.com, Lichess, or from your own PGN files.

Once a game is loaded, every position can be queried directly against ChessDB, making it easy to pause at any moment and see what ChessDB suggests from that exact board state.

2. Board editor for custom positions and FEN input

Not all analysis starts from a game. The board editor lets you construct positions manually or paste a FEN and immediately query ChessDB. This is useful for exploring opening ideas, testing transpositions, or jumping straight to a critical position without any setup overhead.

3. Candidate move table: move, score, rank, win rate and notes

This is the core of what ChessDB provides, and the Explorer is designed to surface it clearly.

For any position, ChessDB returns a list of candidate moves, each with structured metadata. In the Explorer, these are presented as a table including:

• Move – the candidate move from the position
• Score – ChessDB’s evaluation for the move
• Rank – the relative strength of the move compared to other candidates
• Win rate – the success rate reported by ChessDB where available
• Note – contextual information and symbols provided by ChessDB

Rather than collapsing this into a single “best move”, the table makes it easy to compare options side by side and understand the landscape of the position.
An optional LLM-based explanation layer can be enabled to describe the position and the candidate moves in plain language, while keeping ChessDB’s data as the source of truth.

4. Play against ChessDB

ChessDB Explorer also lets you play directly against ChessDB, as White or Black, starting from any position. You can play through your own games, test alternative ideas and see how ChessDB responds move by move.

This is especially useful for opening work and exploratory analysis, where you want to interact with the position rather than just read a static table.

5. Export your work as PGN

After analysing, experimenting and playing through lines, you can export the resulting work as a PGN. This makes it easy to store the analysis, share it, or import it into other tools.

Closing thoughts

ChessDB Explorer exists because ChessDB itself is worth exploring properly. The underlying database already provides rich, structured position knowledge. The Explorer wraps that power in a workflow that feels natural when you are analysing games, testing ideas or digging into specific positions.

If you enjoy working with candidate moves, rankings, scores, win rates and notes, and you want that information available while you load games, edit positions, play lines and export results, ChessDB Explorer is built exactly for that.

References

• Prototype interface: https://chessdb.cn/queryc_en/
• ChessDB API: https://chessdb.cn/cloudbookc_api_en.html