Universal Chess Interface

The Universal Chess Interface (UCI) is an open communication protocol that enables a chess program's engine to communicate with its user interface.

History

In November 2000, the UCI protocol was released. Designed by Rudolf Huber and Stefan Meyer-Kahlen, the author of Shredder, UCI rivals the older "Chess Engine Communication Protocol" introduced with XBoard/WinBoard. Both protocols have been free to use without license fees.

In 2002, Chessbase, the chess software company which markets Fritz, began to support UCI, which had previously been supported by only a few interfaces and engines.

As of 2007, well over 100 engines are known to directly support UCI.

Design

By design, UCI assigns some tasks to the user interface (i.e., presentation layer) which have traditionally been handled by the engine (at the business layer) itself.

Most notably, the opening book is usually expected to be handled by the UI, by simply selecting moves to play until it is out of book, and only then starting up the engine for calculation in the resulting position. UCI does not specify any on-disk format for the opening book. Different UIs usually have their own proprietary formats.

While the UI can also take responsibility for handling endgame tablebases, this is arguably better handled in the engine itself, as having tablebase information can be useful for considering possible future positions.

The move format is in long algebraic notation.

A "nullmove" from the Engine to the GUI should be sent as 0000.

Examples:

• e2e4
• e7e5
• e1g1 (white short castling)
• e7e8q (for promotion)

See also

• Chess Engine Communication Protocol
• Shredder
• XBoard

External links

• Latest UCI Engines (February 2014)
• UCI technical specification download page
• UCI technical specification (online)