Efim Geller – "The Theory Killer"

Efim Geller (1925–1998) was a titan of Soviet chess. A two-time USSR Champion, he was famous for his deep opening preparation and tactical sharpness.

Statistically, he was one of the greatest "giant killers" in history. He had a lifetime winning record against four undisputed World Champions: Botvinnik, Smyslov, Petrosian, and Fischer.

Geller played a universal but sharp style. He was an expert in complex, dynamic openings like the King's Indian and the Sicilian Najdorf, backing them up with concrete calculation.

Yes. After his peak, he served as a coach for World Champions Boris Spassky and Anatoly Karpov, helping them with his encyclopedic opening knowledge.

Geller won 5 games, lost 3, and drew 2 against the legendary Bobby Fischer. Fischer respected Geller immensely.

He defeated the "Patriarch" Mikhail Botvinnik 4 times to 1 loss, dominating him in tactical complexities.

Even the invincible defender Tigran Petrosian struggled against Geller. Geller had a +5 winning record against him.

He won the Soviet Championship, arguably the toughest tournament on Earth, in 1955 and 1979 (at age 54!).

Along with Bronstein and Boleslavsky, Geller established the King's Indian Defense as a top-tier opening.

He qualified for the Candidates cycle six times (1953, 1956, 1962, 1965, 1968, 1971), consistently remaining in the world's top 10.

Botvinnik famously said, "Before Geller, we did not understand the King's Indian." Geller constantly found new moves that revitalized entire systems.

He was Boris Spassky's second during the 1972 "Match of the Century" against Fischer, providing critical opening prep.

He later joined Anatoly Karpov's team, helping the positional genius navigate sharp opening variations.

He won the prestigious Hoogovens tournament (now Tata Steel) in 1969, ahead of Botvinnik.

In 1992, he proved his longevity by winning the World Senior Chess Championship outright.

He introduced the sharp line 1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.Nc3 dxc4 5.e4!? (Geller Gambit) in the Slav Defense.

Though famous for openings, he was a complete player. His endgame win against Smyslov (Rook vs Rook + Pawn) is a textbook classic.

He represented the USSR in seven Chess Olympiads, winning team gold every single time.

He also held a plus score against World Champion Vasily Smyslov (+11 -8 =33), proving his dominance over the 1950s generation.

Ironically, despite his fighting style, he was involved in one of the shortest draws in Candidates history (vs Keres), which led to rule changes.

He was one of the first to play the Sicilian Defense with Black consistently at the highest level in the 1950s.

He won numerous brilliancy prizes, including one for a stunning victory over Kotov in 1949.

Geller believed in searching for the "absolute truth" of a position, refusing to play inferior moves just for psychological effect.

Kasparov wrote that "Geller's contribution to modern opening theory is surpassed only by the very greatest World Champions."