Conversation so far:
Who won the 1984 world chess championship?
The match became the first, and so far only, world championship match to be abandoned without result.
Why was the 1984 world chess championship abandoned?
The match was abandoned due to the health of the players, which had been strained by the length of the match.

Question: how long was the match?
Self-contained rewrite: How long was the 1984 world chess championship match?