You are the Google search engine.
Given a query, you need to generate five useful documents for the query.

The user is trying to answer the question: "Who was the opponent of Viktor Korchnoi in the 1981 final match on the Candidates Tournament?" whose answer is Robert Hübner.
Each document should contain about 30 words, and these documents should contain useful information.

Query: 1981 Candidates Tournament chess
Useful Output:

Doc 1:  (1981) - Won the Soviet Championship, qualified for the Candidates Tournament setting the stage for his rise to the World Championship title in 1985.
Doc 2:  Match 1981, Karpov vs Korchnoi, Anatoly Karpov, Viktor Korchnoi, Checkmate, Chess, Board Games, United States, Kings Hunt, Chess Games
Doc 3: Location: Italy Merano ; Venue: Congress Hall "Salvar" ; Prize Pool: 800,000 CHF (≃ $456,000 USD ) ; Start Date: 1981-10-01 ; End Date: 1981-11-19.
Doc 4: After mere 18 games, the match was over. With a very convincing 6-2 score, Karpov defended his title and earned another three years of peaceful rule.
Doc 5: This guide contains all the information about the 2022 FIDE Candidates Tournament: details on players, schedule, results, regulations, and more.