Viacheslav Ragozin (8 October 1908 - 11 March 1962) was a Soviet chess Grandmaster, international arbiter, the World Correspondence Chess Champion. Moreover, he was a chess writer and an editor.

Ragozin was born in St. Petersburg. He achieved great results in the 1930s and became a well-known player in his country. In 1930, he beat a respected Master, Ilyin-Zhenevsky, and got the Soviet Master title. In 1935, Moscow, he won a game against Lilienthal. At the very strong Moscow Tournament in 1936 he defeated Flohr and Lasker and came very close to beat Capablanca, however, the resourceful former world champion saved the game for a draw. He won in 1936, Leningrad, then he tied for second place (behind Levenfish) at the 1937 Soviet Championship. At the 1939 Moscow-Leningrad Tournament he finished third place behind Flohr and Reshevsky, ahead of Keres.

His successes continued in the 1940s, he received first place in 1942, Sverdlovsk. Then he repeated his triumph at the Leningrad Championship in 1945. At the 1947 Chigorin Memorial he finished second, with half point behind Botvinnik.

By the 1950s, he and most of the members of his generation had been overtaken by the new wave players, who came from the Soviet chess school. Despite of this, Ragozin continued his attempts in the Soviet Championship. He competed eleven times in the championship from 1934 to 1956. In the same decade, his best result on international circle was the second place behind Filip at the 1956 Marianske-Lazne Steinitz Memorial Tournament.

Throughout his life he tried almost every aspects of the game and his interest and talent made that possible. In over-the-board chess he became a Grandmaster in 1950, then in 1951 he got the International Arbiter title. Between 1956 and 1958 he focused on correspondence chess and proved his analytical and theoretical knowledge by finishing second place at the second ICCF World Correspondence Chess Championship in 1959 (9 wins, 4 draws, 1 loss). In the same year, he was awarded with the correspondence chess Grandmaster title.

Ragozin was not only successful, but he was a creative chess player as well. With his creative playing style he attracted the attention of the world champion, Mikhail Botvinnik. Botvinnik recognised that Ragozin would be an ideal sparring-partner. They played many secret sparring-matches to help Botvinnik prepare for his world championship encounters. According to some people, Ragozin’s help contributed to Botvinnik’s success.

From 1946 to 1955 he was an author of the Shakhmaty v SSSR chess magazine, then he continued his career as a civil engineer. He was Vice-President of FIDE from 1950 to 1961.

His contributions to opening theories included such system developments, by which we are able to equalize with Black in the Queen's Gambit and Nimzo-Indian variations.

The QGD Ragozin Defence typically contains the following moves: 1.d4 d5 2.c4 e6 3.Nf3 Nf6 4.Nc3 Bb4.

According to Chessmetrics, his highest score was 2699.

Sources: :https://en.wikipedia.org; http://chessmetrics.com