Larsen and Portisch qualified for this match from the Sousse Interzonal (1967). Three more matches were held in parallel: Spassky - Geller Candidates Quarterfinal (1968), Tal - Gligoric Candidates Quarterfinal (1968) and Korchnoi - Reshevsky Candidates Quarterfinal (1968). The draw for pairings had been made in Sousse on 17 November, right after the Interzonal. (1) Each match would be played to 10 games; (2) the first player to get 5.5 points would go to the semifinal. The matches were held in order to select a challenger for Tigran Vartanovich Petrosian, the World Champion.
After the Interzonal, Larsen and Portisch played in Palma de Mallorca (1967) and Monte Carlo (1968) (the latter in early April). Portisch also played in Hoogovens (1968). Based on his rating and recent tournament victories, Larsen started the match as the favorite. The match was played in "Blå Lagunen" (= Plava Laguna), in Poreč, Yugoslavia (today: Croatia). (3, 4) Larsen was accompanied by his wife; (3) Portisch was helped by his second Tibor Florian and his trainer Ferenc Koberl. (5, 6) Chief arbiter was Vladimir Vukovic. (5) Former World Champion Mikhail Botvinnik found it difficult to guess who would win. On balance, he thought that Larsen’s chances may be greater, despite both players being about equal in their grasp of the game. It was Larsen's superior sporting character that he singled out; not necessarily in terms of recovering from a loss, but rather, in his determination to play for a win in all situations. (7)
Game 1 started on 6 May. (8) The play appeared to be nervous and inaccurate right from the opening. It ended with opposite-colored bishops and a draw. In Game 2, Portisch was slightly better and tried to improve his position by an optimistic but risky pawn sacrifice (28...f4). The position got tactical, and Larsen won with three pieces versus queen. Perhaps eager to get immediate revenge, Portisch tried a new "positional" move (11.a4) in Game 3 against Larsen's Nimzo-Indian. Larsen just developed his pieces, won a pawn, and the game. Then, in Game 4, Portisch offered draw in an equal position on move 18. Instead of accepting the offer, and consolidating his lead, Larsen chose to continue, and walked into mate. Peter Hugh Clarke was critical of the Dane; not for playing on, but for playing hard to win in what was a level position. (10) In Game 5, Larsen was able to contribute to the theory of the Meran Variation of the Semi-Slav Defense:
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13...g6!? According to GM Lars Bo Hansen, the move has a sound strategic basis. Black develops his bishop to g7 to put pressure on White's e5-pawn and circumvents White's idea of building a kingside attack by Nxd4 followed by Qg4 or Qh5. The drawback is a weakening of the dark squares. (11) The position has been analyzed by Garry Kasparov. (12) Portisch did not play the most critical 14.Bg5, and the game ended in a draw. In Game 6, Portisch could have played on, with queen versus pawn, rook and knight, but offered the draw instead. This time, Larsen accepted. Portisch's play had improved markedly, and having had the best of two draws, (10) he was able to level the score in Game 7. Well prepared against the Nimzo-Indian, he played 11.Rd1 as in Game 1, but Larsen was fine and at times even better until he blundered with 46...Kxh2 (Stockfish). In Game 8, Larsen switched to 1.e4 and a 'Vienna Game'. It almost paid dividends, but in the end Portisch established a fortress with two bishops versus queen. In the penultimate game, Portisch was much better, but he missed several opportunities, including 53.Nd3! going for Nb4 and the c-pawn. (13) And on move 63:
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Portisch played 63.Nxe6?, but after 63...Bxe6 64.Bxe6 Ng5 65.Bg4 Nf3+ 66.Bxf3 Rxf3, Larsen's rook became active. Draw! According to Florian, Portisch slept badly and was off form when it came to the vital Game 10. (14) A Vienna game again! Carel Benjamin van den Berg noted that the opening choice was a piece of practical psychology which reminded Portisch of Larsen vs Portisch, 1966. (15) He seemed dispirited by his failure to put Larsen to the sword in the previous two games and played below his best. A knight foray to f4 resulted in the loss of the piece and this hastened his demise, in what was the shortest game of the match. (16)
Poreč, Yugoslavia (Croatia), 6-24 May 1968
Larsen advanced to the Spassky - Larsen Candidates Semifinal (1968).
Elo* 1 2 3 4 5 6 7 8 9 0
Larsen 2650 ½ 1 1 0 ½ ½ 0 ½ ½ 1 5½
Portisch 2610 ½ 0 0 1 ½ ½ 1 ½ ½ 0 4½
1) The Times, 18 November 1967, p. 5.
2) Tidskrift för Schack, June 1968 (vol. 74), p. 135.
3) Dragoslav Andric in Tidskrift för Schack, September 1968 (vol. 74), p. 194.
4) Wikipedia article: Pore%C4%8D.
5) Schach (Berlin DDR), 7/1968, p. 202.
6) Johann Oern Sigurjonsson in Vísir, 1 June 1968, p. 7.
7) Mikhail Botvinnik in British Chess Magazine, June 1968, p. 158.
8) bilten Meča turnira kandidata za šahovsko prvenstvo svijeta. 10 pp. (match bulletin).
9) Tidskrift för Schack, July-August 1968, p. 170.
10) British Chess Magazine, July 1968, p. 186.
11) Improve Your Chess, by Lars Bo Hansen. Gambit Publications 2009, p. 155.
12) My Great Predecessors, Vol. IV, by Garry Kasparov. Everyman Chess 2004, p. 188.
13) Aleksandar Matanovic in CHESS, July 1968, p. 318.
14) Harry Golombek in The Times, 29 June 1968, p. 26.
15) De Telegraaf, 29 June 1968, p. 37.
16) Peter Hugh Clarke in British Chess Magazine, August 1968, p. 230.
*Unofficial FIDE Rating List April 1968 (http://www.olimpbase.org/Elo/Elo196...). Suggested reading: analyses by Larsen in Skakbladet (Denmark), June 1968 pp. 93-97 (games 1-5) and July 1968 pp. 105-110 (games 6-10).
Original collections: Game Collection: WCC Index (Larsen-Portisch 1968) by User: Hesam7 and Game Collection: Larsen - Portisch Candidates Quarterfinal 1968 by User: Tabanus. Game dates are from the match bulletin (see note 8). Thanks to User: whiteshark for information from Schach (Berlin DDR), and to User: Paint My Dragon for information from CHESS and BCM. User: OhioChessFan improved the English.