Alfil

He used the alfil to beat me at chess.

Source: tatoeba (12204471)

In problems with unorthodox pieces the convention is usually followed that they have appeared by promotion of pawns, though this is not sufficient in some cases (e.g. alfils and equihoppers may not be able to get to the required square from the promotion rank). […] The earliest known example of a partial rider is the Talia (meaning scout) which occurs in the Great Chess of Timur. It is a transition piece between the mediaeval alfil and the modern bishop, able to move like the bishop without being blocked by a pawn standing in front of it.

Source: wiktionary