Lajos Portisch (born 4 April 1937) is a Hungarian chess Grandmaster, whose positional style earned him the nickname, the "Hungarian Botvinnik". One of the strongest players from the early 1960s into the late 1980s, he participated in twelve consecutive Interzonals from 1962 through 1993, qualifying for the World Chess Championship Candidates Cycle a total of eight times (1965, 1968, 1974, 1977, 1980, 1983, 1985, and 1988). Portisch set several all-time records in Chess Olympiads. In Hungarian Chess Championships, he either shared the title or won it outright a total of eight times (1958, 1959, 1961, 1964, 1965, 1971, 1975, and 1981). He won many strong international tournaments during his career. In 2004, Portisch was awarded the title of 'Nemzet Sportolója' (Sportsman of the Nation), Hungary's highest national sports achievement award.

His main hobby is singing operatic arias; he has a fine baritone voice, a quality shared by Vasily Smyslov, a chess world champion and grandmaster who also had talent as an operatic singer. His younger brother, Ferenc (born 1939), is an International Master.

Portisch represented Hungary at the World Junior Chess Championship, Antwerp 1955. He scored 4½/7 in the preliminary round to advance to the final, where he scored 5½/9, to finish fourth; the winner was Boris Spassky. Portisch tied for first through third places in a master event at Budapest 1956, along with József Szily and Béla Sándor, ahead of Pal Benko; the three winners scored 7/11. In a second master event at Budapest 1956, Portisch made 7½/11. He was in the pack at Debrecen 1956 with 5½/11.

Portisch successfully represented Hungary in several team matches in 1956 and 1957, against Poland, Estonia, the Soviet Union, Belarus, and Yugoslavia. He made his first Student Olympiad and full Olympiad appearances for Hungary in 1956; he would eventually represent Hungary at a record twenty Olympiads (see below). He excelled at his first individual international event, winning at Balatonfüred 1958 with 9/11, ahead of strong Grandmasters László Szabó and Alexander Tolush. He earned the International Master title. He finished second at Hastings 1958–59 with 7/9, behind Wolfgang Uhlmann.

Portisch made his first national top-level appearance in 1955 at age 18, at the Hungarian Chess Championship. He would eventually win or share the national title on nine occasions. His complete Hungarian Championship results follow (from chessmetrics.com).

In the World Chess Championship cycles, Portisch played in every Interzonal from 1962 to 1993, twelve in total. He qualified for the next stage, the Candidates Tournament, eight times: in the 1966, 1969, 1975, 1978, 1981, 1984, 1987 and 1990 cycles; with his best results when he reached the Candidates semi-finals in 1977 and 1980.

Portisch entered the World Championship cycle for the first time with the Madrid 1960 Zonal, where he tied for second/third place, on 13½/21, along with Arturo Pomar; the winner was Svetozar Gligorić, as all three advanced. Portisch was awarded the grandmaster title by FIDE in 1961.

Portisch's first Interzonal appearance was the 1962 Interzonal in Stockholm, where he tied for ninth/tenth places, after losing a late-round game to one of the tail-enders, and did not advance to the Candidates Tournament.