# official-pikafish/Pikafish

A free and strong UCI xiangqi engine

Repository: https://github.com/official-pikafish/Pikafish
Canonical: https://ross.abutalabs.com/products/pikafish
Homepage: https://pikafish.com
Language: C++
License: GPL-3.0
License Family: copyleft
Topics: xiangqi, uci, pikafish, cpp, xiangqi-engine
Last push: 2026-08-25T16:49:47+00:00

## Health v2 (maintenance only)
Score: 76/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 99, release rhythm 32, longevity 100
- inputs: {"age_days": 1498, "days_push": 8, "days_rel": 243, "gap_med": 193, "n_releases_24m": 2}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1963, forks 359 (observed 2026-08-28T04:05:59.697026+00:00)

## What it is
Pikafish is a free, open-source UCI xiangqi (Chinese chess) engine derived from Stockfish, using NNUE neural network evaluation to analyze positions and compute optimal moves. It ships as a headless engine without a GUI, designed to be paired with third-party chess interfaces.

## Use cases
- play against a strong xiangqi engine
- analyze Chinese chess positions and find best moves
- add a UCI xiangqi engine to a chess GUI
- study xiangqi openings and endgames with engine analysis
- run engine matches between xiangqi programs
- contribute to open-source game AI development

## When to choose
- you need a powerful, actively developed open-source xiangqi engine
- you already have a UCI-compatible GUI and just need the engine
- you want NNUE-based evaluation strength comparable to Stockfish
- you need cross-platform support (Windows, Linux, macOS) with CPU instruction-set optimizations

## When to avoid
- you want a complete app with a built-in graphical board out of the box
- you need engines for chess or other games rather than xiangqi
- you require a commercial-use license without checking the commercial authorization list
- you need a web-based opponent without any setup (use the official web version instead)

## Facets
- artifact type: application
- maturity: active
- function: game-engine, machine-learning, cli
- domain: gaming-tools, artificial-intelligence
- platform: windows, cpp, cli
- tags: xiangqi, chinese-chess, uci, nnue, stockfish-derived, board-game-ai, game-development, linux, macos

## Member repositories
- official-pikafish/Pikafish (main) score 76

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:59.697026+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T03:05:33.605988+00:00, confidence not recorded.
  - readme: https://github.com/official-pikafish/Pikafish (fetched 2026-08-28T04:05:59.697026+00:00, sha 665bb48d72fb)
  - homepage: https://pikafish.com (fetched 2026-08-29T10:45:49.905028+00:00, sha 0846015fcb2f)
- Data as of 2026-08-30T08:39:29.467469+00:00.