Overview
At the crux of the game was a word chain. In the chain, each of eight words (seven starting in 1986) was connected to both the word above it and the word below it in some way. By making inferences based on the revealed words and the revealed letters in incomplete words, contestants tried to fill in the word chains to score points (dollars on GSN). The team/player that reached the point/money goal first would win the game and play the bonus round, which was completely different depending on the series.
Read more about this topic: Chain Reaction (game show)