Philadelphia ? He was the ultimate cold warrior, humbling the mighty Soviet chess establishment through his own genius and a pounding ambition to be the best player in the world.

At a time when competition with the Soviets was being measured in moon landings and missile counts, Bobby Fischer proved that the United States could achieve mastery of an intellectual battlefield where knights and kings clashed on a black-and-white board.

But Fischer’s own government once believed his mother might be a Soviet spy, and that Moscow might have tried to enlist young Bobby as well.

FBI documents obtained by The Philadelphia Inquirer under the Freedom of Information Act show that intermittently, from the 1940s to the early 1970s, the Fischers were being watched.

The FBI worried that the Russians had tried to recruit the young chess prodigy in a trip he made to Moscow in 1958.

Agents also suspected that his mother, Regina, might have been a Soviet operative.

J. Edgar Hoover’s agents interviewed informants, posed as student journalists, and considered cultivating other chess players. They hounded Fischer’s mother, reading her mail, questioning her neighbors, studying her canceled checks.

It all yielded little in the way of intelligence. The FBI concluded Regina Fischer was no spy, and that the Soviets had not tried to recruit her son.

Deep secrets

But the FBI files and other documents offer insights into long-buried secrets about who Bobby Fischer is and who his parents were.

U.S. Chess Champion Bobby Fischer , the eccentric chess prodigy who dueled Soviet grand masters and won a world title in 1972, was investigated by FBI agents who suspected his mother was a communist spy, according to the bureau's records. FBI files obtained by The Philadelphia Inquirer under the Freedom of Information Act show that the government watched the Fischer family for three decades and at one point feared that Soviet agents had tried to recruit Fischer himself.

Fischer’s father has widely been identified as a German biophysicist named Hans-Gerhardt Fischer. But documents suggest it was someone else entirely.

The FBI kept a file on that man, too.

The files offer glimpses into the world of Hoover’s FBI, where agents in the Cold War pursued citizens of leftist leanings with a fevered intensity and few restraints.

Now 59, Bobby Fischer has become a reclusive, anti-Semitic expatriate. Efforts to interview him for this article were unsuccessful.

Fisher cheered 9-11

He has been seen in Japan, Hungary and the Philippines. In a Philippine radio interview on Sept. 11, 2001, he applauded the terrorists’ attacks and said America should be “wiped out.”

Chess experts have analyzed Fischer’s games in astonishing depth. Even the offhand games he played blindfolded have been exhumed and published like lost works of literature.

But his life is largely a mystery. Bruce Pandolfini, a noted chess teacher who was featured in the movie “Searching for Bobby Fischer,” said of Fischer’s beginnings: “Nothing is known.”

Despite playing well in Moscow in 1958, Fischer was peeved at not being matched with the Soviets’ best.

The FBI heard from another informant: Fischer had called his mother in the United States and told her, “It’s no good here.”

Agents weren’t sure what to make of that. So they guessed.

“(I)t is possible that the Soviets may have made an approach to Robert Fischer to which the youth took exception,” Hoover’s office wrote to the New York field office in September 1958.

After beating Boris Spassky for the world title in 1972, Fischer dropped out of competition.

He resurfaced in 1992 to beat Spassky again, in Yugoslavia. That got Fischer indicted: the Justice Department alleged he had violated U.N. sanctions imposed on Yugoslavia. If Fischer reenters the United States, prosecutors say, he faces arrest.