The World Open chess tournament is an annual open chess tournament played in most editions in Philadelphia and some editions in New York City. The inaugural event was a huge success played in New York in 1973 with 732 participants, and was won by Walter Browne.
The tournament is divided into different sections, with typically 100–200 players in the top section. The 1986 edition had as many as 1507 participants, arguably a world record for a chess tournament. The 2009 edition had 1350 players divided into nine sections. The total prize fund was US$250,000 (first prize in the top section US$15,200). It is usually played in the first week of July, sometimes beginning at the end of June. All editions have been organized by the Continental Chess Association.
All players finishing equal first are listed; the winners after tie-breaks are boldfaced.