Chain Reaction was an American game show seen on the NBC network in 1980, and the USA cable network in the late 1980s and early 1990s. Bill Cullen, Blake Emmons and Geoff Edwards hosted this word game created by Bob Stewart.

Chain Reaction was among the first Bob Stewart-produced game shows to originate from Southern California.

Overview
At the crux of the game was a word chain. In the chain, each of eight words was connected to both the word above it and the word below it. 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. The team or player that reached the point goal first (50 on NBC, from 200 to 500 on USA) would win the game and play the bonus round, which was completely different depending on the series.


NBC
The first version of Chain Reaction aired from January 14 to June 20, 1980. It was one of three shows (along with High Rollers and Hollywood Squares) that were canceled to make room for David Letterman's short-lived daytime talk show. The day is considered by game show purists as Black Friday. To make matters worse, The $20,000 Pyramid left the air a week later on ABC.


Main game
Two teams of three competed in each game. A team consisted of one contestant and two celebrity guests. The teams were shown the beginning and ending words of an eight word chain. Each word somehow related to the word above it and below it. A sample chain could be:

CHAIN
GANG
FOUR
SQUARE
DANCE
PARTY
TIME
FLIES


As the game continued, the words would be revealed, making it easier to fill in the blanks. A player's turn consisted of calling for a letter in the next word above or below one of the words, and deciding to give the task of guessing that word to the next person on his own team, or challenging the next person in line on the opposing team to guess (note that the last letter of each word is not revealed). A correct response won one point for each letter in the word (two if the word had a '+' mark next to it) and that team kept control of the board. If the player in control was incorrect, or gave no guess, control went back to the other team. The game continued until either one team scored 50 points, or the chain was finished. If that happened, another chain was put up and the game continued until one team reached the goal of 50 points. That team's contestant won the game, $250, and the right to play for $10,000 in the bonus round. The losing player got $5 a point for playing.


Instant Reaction
In the bonus round, the team had 90 seconds (originally 60) to get the contestant to guess a series of words or phrases. The catch was that the two celebrities had to construct a question for the clue word, and they could only contribute one word at a time. After the celebrities finished the question, they prompted the contestant to guess by ringing a bell. A correct answer moved closer to the grand prize $10,000, an incorrect answer or a pass cancelled that word and they had to move on.


Prize Levels
Starter: $ 1
2 right: $ 10
4 right: $ 100
6 right: $ 1,000
8 right: $10,000


Progress was tallied by lighting up half a zero for each correct answer. If the team could not get all the right answers in time, the contestant won however much money they had accumulated.

The above prize table was used for one week, after most contestants were unable to get past the $10 or $100 levels. To overcompensate, the producers changed the prizes:

1 right: $ 1
2 right: $ 10
3 right: $ 100
4 right: $ 1,000
5 right: $ 2,000
6 right: $ 3,000
7 right: $ 4,000
8 right: $ 5,000
9 right: $10,000


This payoff schedule caused many contestants to win several thousand dollars without winning the grand prize, and so they changed one more time:

For the third payoff version, each right answer in 90 seconds was worth $100, with ten right winning $10,000. Thus:
1 right: $ 100
2 right: $ 200
3 right: $ 300
4 right: $ 400
5 right: $ 500
6 right: $ 600
7 right: $ 700
8 right: $ 800
9 right: $ 900
10 right: $10,000


After that, a change was made so that the game was played for points only, instead of $5 a letter. The loser would win parting gifts instead. The game's champion won $100, and that $100 was posted on the scoreboard. From then on to the end of the show's run, only nine answers were needed to win the $10,000.

In any case, the team then went back to play another game, with a new contestant. Contestants stayed on until they lost in the main game, or won five times.

The NBC version went through all these changes in only 13 weeks. While Bill Cullen took two weeks off to host Password Plus for Allen Ludden, Geoff Edwards was brought in to replace him; he would eventually host the 1980s version.

The "forming questions one word at a time" concept of the Instant Reaction round was once used in a failed Bob Stewart game show pilot called Get Rich Quick with future Good Day L.A. host Steve Edwards as the host. The format later became the basis of another Bob Stewart-produced game show, Go, which aired on NBC in 1983.


USA
The USA network chose "Chain Reaction" to be their third original game show (Love Me, Love Me Not and a revival of Jackpot! were aired earlier) thanks to reruns of the original Chain Reaction. Geoff Edwards hosted the show for the first few weeks before being replaced by Blake Emmons. He hosted the show for a few weeks, then replaced by Edwards again. Rod Charlebois was the co-host/announcer, who presented the "home game" for the viewing audience. Rod was given an on-air role because the show was taped in Canada, and all Canadian television programs must have at least one Canadian person on the air each day, and Edwards, unlike Emmons, was not Canadian. Nonetheless, Edwards commuted between California and Toronto (like Jim Perry, who was also working on both sides of the U.S./Canadian border at that time).

The teams were now two civilian players each, and each was given one responsibility (giving/receiving letters, and guessing words). Each word in the chain was worth 10 points, and the last worth 20 (later 15). The second chain had words worth 20/40 points, then the third chain had 30/60 points, The first team to score 200 points (later 300, then 500) won the game. That team played the bonus game, and returned on the next show.


Bonus Chain
The winning team could collect the cash jackpot by completing one last word chain. The team was shown the first word in a chain, and the initial letter of the other words. One at a time, the players would guess at the next word in the chain. For each wrong guess, the next letter would be filled in, and a letter deducted from their account. If the team could finish the chain before running out of letters the team won the money. The jackpot began at $3,000; and $1,000 was added each day it was not claimed. While Emmons was host, the account was nine letters, when Geoff Edwards took over, it was lowered to seven.


The $40,000 Tournament
The game now was played with single players. The game was just like before, but there was no bonus chain, and contestants tried to win their weekly tournament worth $7,500. The sixteen winners moved on into the grand tournament, where the final winner collected $40,000. The player who led after the second chain (the last word of the first chain was worth 15 points in order to break a potential 90-90 tie) got to play a Missing Link game for bonus money. The champ was shown a chain like that of the home game, and could guess the word for $300. If wrong, a letter would be shown and the value dropped to $200. Another letter could be revealed and the prize was $100.


Home Game
Each day, before closing the show, Rod would present the answer to yesterday's home game, and the current game. The home game consisted of a three word chain, with the top and bottom words revealed. It was up to the home audience to figure out what word connected with both words. Sometimes Rod would reveal the first letter of the 'missing link,' sometimes he wouldn't.

All cash values for the USA version are in Canadian dollars.