Chain Reaction is an American television game show created by Bob Stewart, in which players compete to form chains composed of two-word phrases. The show has aired five separate runs: Bill Cullen hosted the original series on NBC from January 14, 1980, to June 20, 1980. The second version aired on the USA Network from September 29, 1986, to December 27, 1991, and was hosted first by Blake Emmons and later by Geoff Edwards (who also subbed for Cullen for two weeks on the NBC version). A third version aired on Game Show Network from August 1, 2006, to June 9, 2007, hosted by Dylan Lane. A fourth version, also on GSN, was announced on January 26, 2015, with Vincent Rubino as executive producer and hosted by Mike Catherwood. Forty episodes were ordered for Catherwood's version, which aired from July 16, 2015, to January 29, 2016. The fifth and current version, also on GSN, was announced in November 2020, with Mike Richards as executive producer, Ed Egan as showrunner and Lane returning as host; it premiered on February 22, 2021. Overview The game is centered around solving a word-chain puzzle. In 1980, the chain comprised eight words. From 1986 to 2016, it comprised seven words, and in 2021, it comprised six words for the first three rounds and seven in the fourth. The words in the chain are linguistically or logically connected, with both the word at the top and the word at the bottom revealed on the outset. By making inferences based on the revealed words and the revealed letters in incomplete words, contestants try to fill in the word chains to score points (dollars on Game Show Network). From 1980 to 1991, the team/player that reached the point goal first won the game. Since 2006, the team with the highest money total after the fourth round wins the game; a team can also win the game if at any time their opponents' money total is reduced to zero during the fourth round. Except from 1990 to 1991, the winning team/player then played the bonus round, which would vary depending on the series. NBC The first version of the show aired for 23 weeks from January 14, 1980, to June 20, 1980, on NBC and was hosted by Bill Cullen, except for two weeks when Geoff Edwards hosted while Cullen was filling in for Allen Ludden on Password Plus.