reti

A CQL-first repository for chess endgame analysis.

The core of this project is the cql-files/ tree: collections of Chess Query Language scripts for identifying endgames and positions in PGN databases. The Python code in src/reti/ exists to run those scripts and summarize results at the command line.

Repository layout

• cql-files/: the main script collections, including the FCE material
• src/reti/repair_pgn.py: one-time in-place PGN repair and normalization before CQL runs
• src/reti/analyse_cql.py: batch CLI runner for pgn|dir x cql|dir matrix execution
• src/reti/export_cql_positions.py: exports {CQL}-annotated PGN positions to an evaluated CSV
• src/reti/fce_sankey.py: core logic for building an interactive FCE transition Sankey
• scripts/build_fce_table_subset.py: builds the curated FCE subset used for the public table workflow
• scripts/render_fce_table_from_summary.py: renders markdown table rows from analyse_cql.py output
• scripts/render_fce_sankey.py: renders a standalone interactive Sankey HTML file from annotated FCE PGNs
• tests_cql/: fixtures and tests for the CQL scripts
• docs/analyse_cql.md: detailed documentation for the batch CQL runner
• docs/export_cql_positions.md: detailed documentation for exporting annotated positions to CSV
• docs/fce_sankey.md: workflow for turning annotated FCE PGN output into a public static Sankey page
• docs/fce_table.md: workflow for building the curated FCE table subset and rendering the final table
• docs/repair_pgn.md: one-time PGN repair workflow for CQL-unfriendly databases

Install

python -m venv .venv
source .venv/bin/activate  # use .venv\Scripts\Activate.ps1 on Windows
pip install -e .

You will also need a CQL binary. You can point the scripts at any installed cql executable. If you keep a private local copy under bins/, that directory is ignored by Git; the test and CLI resolution logic will still pick it up automatically.

CLI usage

Run the batch CQL runner:

python src/reti/analyse_cql.py \
  --pgn path/to/pgn_or_dir \
  --cql-bin path/to/cql \
  --scripts path/to/script_or_directory \
  --jobs 1 \
  -o path/to/output_dir

src/reti/analyse_cql.py accepts either a single PGN or a directory of PGNs, and either a single CQL script or a directory of CQL scripts. It runs the full cross-product and writes one output PGN per pair plus a summary.csv. During preflight, if a PGN contains text-level incompatibilities that older CQL builds dislike, the runner uses a sanitized temporary copy for that run and leaves the original PGN untouched. By default the preflight stays cheap; deeper PGN parser checks and the up-front CQL smoke test are both opt-in flags. The runner now defaults to sequential job execution so CQL can use its own internal threading without process-level oversubscription.

Detailed usage, output layout, and examples are in docs/analyse_cql.md.

If a PGN makes CQL abort, repair it once in place before analysis:

python src/reti/repair_pgn.py \
  --pgn ~/Downloads/LumbrasGigaBase_OTB_1900-1949.pgn \
  --cql-bin ./bins/cql6-2/cql

That rewrites the PGN through a streaming sanitize-and-normalize pass and only replaces the original file if the repaired temp copy passes a CQL smoke test. If you want the rewrite to finish as quickly as possible and are willing to skip that extra validation pass, omit --cql-bin. The repaired output is intentionally CQL-safe: it keeps headers and mainline moves, but drops comments and side variations. Full details are in docs/repair_pgn.md.

If you already have PGNs containing {CQL} move comments, export those marked positions to CSV like this:

python src/reti/export_cql_positions.py \
  --pgn path/to/annotated_pgn_or_dir \
  --output-csv output/cql_positions.csv \
  --syzygy-dir /path/to/syzygy \
  --stockfish-bin path/to/stockfish

For marked positions with 5 pieces or fewer, the exporter uses Syzygy. For larger positions, it uses Stockfish for a configurable fixed time budget per position. The CSV includes the source PGN, ending label from the PGN filename, move context, FEN, and raw evaluation fields. Do not run repair_pgn.py on these annotated PGNs first: the repair step deliberately strips comments. Full details are in docs/export_cql_positions.md.

For the FCE table workflow, first build the curated subset:

python scripts/build_fce_table_subset.py

Then run the batch analysis over your PGN directory and render the markdown table:

python src/reti/analyse_cql.py \
  --pgn path/to/pgn_dir \
  --cql-bin path/to/cql \
  --scripts cql-files/FCE/table \
  --jobs 1 \
  -o output/fce-table
python scripts/render_fce_table_from_summary.py output/fce-table/summary.csv path/to/pgn_dir

Detailed FCE instructions are in docs/fce_table.md.

If you want an interactive web-facing view of how games move between FCE endings, render the annotated output PGNs directly into a standalone HTML Sankey:

python scripts/render_fce_sankey.py \
  --pgn-dir output/fce-table \
  --output-html docs/fce_sankey.html

That HTML file uses Plotly from a CDN and can be published as-is on GitHub Pages or any other static host. Full details are in docs/fce_sankey.md.

FCE table reference

Reference table from https://en.wikipedia.org/wiki/Chess_endgame#Frequency_table

ID	Ending	Quantity	Percentage
1.4	Bishop + Knight vs King	283 (62 draws)	0.02
2	Pawn Endings	48,465	2.87
	King + Pawn vs King	3,920	0.23
3.1	Knight vs Pawns	15,512	0.92
3.2	Knight vs Knight	26,263	1.56
4.1	Bishop vs Pawns	16,953	1.01
4.2	Bishop vs Bishop (Same Colour)	27,864 (11,351 draws)	1.65
4.3	Bishop vs Bishop (Opposite Colour)	18,653 (11,045 draws)	1.11
5	Bishop vs Knight	55,476 (19,670 draws)	3.29
6.1	Rook vs Pawns	12,723	0.75
6.2	Rook vs Rook	142,488 (55,974 draws)	8.45
6.2 A1	Rook + Pawn vs Rook	11,318	0.67
6.2 A2	Rook + Two Pawns vs Rook	9,398 (3,574 connected)	0.56
6.3	Two Rooks vs Two Rooks	58,211	3.45
7.1	Rook vs Knight	16,298	0.97
7.2	Rook vs Bishop	25,524	1.51
8.1	Rook + Knight vs Rook	23,910 (467 without pawns; 418 draws)	1.42
8.2	Rook + Bishop vs Rook	29,785 (736 without pawns; 401 draws)	1.77
8.3	Rook + Minor Piece vs Rook + Minor Piece	255,317	15.13
9.1	Queen vs Pawns	7,066	0.42
9.2	Queen vs Queen	30,834	1.83
9.3	Queen + Pawn vs Queen	1,575	0.09
10.1	Queen vs One Minor Piece	2,798	0.17
10.2	Queen vs Rook	6,769 (263 without pawns and 10 half-moves; 22 draws)	0.40
10.3	Queen vs Two Minor Pieces	1,276	0.08
10.4	Queen vs Rook + Minor Piece	11,637	0.69
10.5	Queen vs Two Rooks	5,257	0.31
10.6	Queen vs Three Minor Pieces	239	0.01
10.7	Queen and Minor Piece vs Queen	15,128	0.90
	Queen + Bishop vs Two Rooks	Only one without pawns!	0.00006