Changes

[[FILE:Hurricane Betsy.jpg|border|right|thumb| Hurricane Betsy <ref>[https://en.wikipedia.org/wiki/Hurricane_Betsy Hurricane Betsy] in the [https://en.wikipedia.org/wiki/Gulf_of_Mexico Gulf of Mexico] in September of 1965 as taken by the [https://en.wikipedia.org/wiki/Television_Infrared_Observation_Satellite TIROS-8] weather satellite. Source: [https://en.wikipedia.org/wiki/National_Oceanic_and_Atmospheric_Administration NOAA] [http://www.photolib.noaa.gov/ Photo Library], September 4, 1965</ref> ]]

a [[WinBoard]] compatible chess engine by [[Landon Rabern]], written in [[C]] with a little [[Assembly]], released in September 2000 <ref>[https://web.archive.org/web/20131109133342/http://wbec-ridderkerk.nl/html/details1/Betsy.html Betsy] from [[WBEC|WBEC Ridderkerk]] ([https://en.wikipedia.org/wiki/Internet_Archive Internet Archive])</ref>.

Originally written in [[Pascal]] with its own [[CLI|text interface]] it was rewritten in C using [[Rotated Bitboards|rotated bitboards]]. Betsy applies [[Principal Variation Search|PVS]] with [[Null Move Pruning|null move pruning]], and various standard and some aggressive non-standard [[Extensions|extensions]] and [[Reductions|reductions]].