BERLIN, December 2 Armin Meiwes, the German computer expert who gained worldwide notoriety by killing and eating a willing victim, stands trial on Wednesday in a case of sexually inspired cannibalism so perplexing it could make legal history.

Meiwes, 42, described by his lawyer as a ‘‘gentleman of the old school’’, has confessed to killing a Berlin man who answered an ad he had posted on the Internet seeking a fit man ‘‘for slaughter’’.

They met in Meiwes’s elegant half-timbered home in the town of Rotenburg, central Germany, in March 2001. Meiwes killed the man, named only as Bernd-Juergen B., with a kitchen knife and filmed the deed on video tape which may be shown at the trial. Meiwes’s lawyer Harald Ermel said it took the victim nearly 10 hours to bleed to death and that he had repeatedly urged Meiwes to keep on cutting him.

Meiwes stored body parts in his freezer. ‘‘He believes he ate 20 kg and there were about 10 kg left over,’’ said Ermel. ‘‘He defrosted it little by little and ate it.’’ Police arrested Meiwes a year later, in December 2002, after a tip-off from someone who had spotted another of his adverts on the Internet.

Meiwes told German newspaper Welt am Sonntag last week: ‘‘I am guilty and regret what I did.’’ He said he had eaten his victim because he wanted to make him part of himself, a desire that he had satisfied and that would not recur.