Mr. Berliner, playing Black, essayed the Two Knights Defense, one of the more complicated openings. For many months, the players traded what would be described as haymakers in boxing, with each attacking, only to be met with a counterattack. After an incredible series of moves, the game wound down to a rook-and-pawn ending that Mr. Berliner won.
Andy Soltis, a grandmaster of over-the-board (conventional) play, ranked the game No. 1 in his book “The 100 Best Chess Games of the 20th Century” (2000). Over the years, the game was often analyzed by people using increasingly powerful chess computers, but only a few small improvements in the moves of both players were ever found.
Mr. Berliner was also an accomplished over-the-board player. He was an international master (the rank just below grandmaster) and played in several United States Championships in the 1950s and early ’60s.
In the early 1960s, inspired by the work of programming pioneers in artificial intelligence, Mr. Berliner, who was working at IBM at the time, began writing a program to play chess.
At 40, just after becoming world correspondence champion, Mr. Berliner entered Carnegie Mellon University to pursue a doctorate in computer science. Afterward, he joined the university’s faculty.
As he worked to create a chess computer, he realized that the approach he had previously used, trying to get a computer to use logic, was never going to be as effective as brute force — having the computer analyze as many moves as possible. The problem was that the number of possible moves in a chess game is estimated to be the same as the number of atoms in the universe. How could a computer tackle such a task?
He decided to look for a solution by programming a computer to play what he thought was a simpler game: backgammon. But that was also incredibly complex. There were about 60 possible moves at any one time and 21 possible results from the roll of the dice.
He designed a program that played well up to a point, but invariably something would go wrong. He analyzed the problem and discovered the computer made mistakes when the situation in the game began to change — for example, the computer went from having a clearly better position to one in which the outcome was in doubt — and the program failed to adjust its strategy. He applied fuzzy set theory to allow the program to make estimates of possible outcomes, and that worked.
In July 1979, the newly redesigned program, called BKG 9.8, played and won a match, 7-1, against Luigi Villa, the reigning world backgammon champion. Mr. Berliner’s program thus became the first to defeat a world champion at any board game, though he acknowledged that the program had better dice rolls than Mr. Villa throughout the match.
Mr. Berliner returned to building a chess computer, working with some of his students, including Mr. Eberling, who went on to become one of the country’s best-known computer experts, and Murray Campbell, who was later part of the team that designed and built Deep Blue, the computer that beat Garry Kasparov, the reigning champion, in 1997.
In spring 1985, the new computer, HiTech, made its debut. It quickly ascended to the rank of master and then to senior master, becoming the world’s strongest chess computer. In 1988, it became the first computer to beat a grandmaster in a match, defeating Arnold Denker, 3.5 to 0.5, though Mr. Denker was well past his prime.
In an email, Mr. Ebeling recalled Mr. Berliner as demanding but fair. “One of my fondest memories,” he wrote, “was working with him one day on a breakthrough idea that completely changed how we designed HiTech. It was an insightful question about how to use the hardware, which he didn’t really understand, that sparked the new ideas.”
Mr. Berliner was born in Berlin on Jan. 27, 1929. His father was an electrical engineer, and his mother a homemaker. His great-uncle was Emile Berliner, who had invented recording discs, otherwise known as records.
In 1937, amid the rise of Nazism, Mr. Berliner’s family emigrated to Washington, D.C. He learned to play chess at 13 during a rainy day at summer camp.
He became a chess master at 20 and by 23 was good enough to be part of the United States team that played in Helsinki at the biennial Chess Olympiad.
Mr. Berliner, who lived in Riviera Beach, was married twice. He is survived by a brother, Ernest.
In a 2005 interview with the Computer History Museum, Mr. Berliner said that one of the most exciting times of his life was in 1985, when HiTech was first being put together. There were so many parts, he recalled, that he was not sure if it would work.
“Sooner or later, the moment of truth comes where you put them all together and see what it does,” he said. “And from the very beginning, I could see that it had the potential — maybe not every single time — it had the potential to play better than any device that existed.”