Her dismembered body was later found in a cave in the remote fishing village of Miura outside Tokyo, close to the accused Joji Obara's home, seven months after she had disappeared.
Property developer Mr Obara, 54, will have his verdict decided by a Tokyo district court as father Tim Blackman and Lucie's sister Sophie, 26, witness the decision.
The prosecution allege that Mr Obara drugged and raped Ms Blackman before dismembering her body and encasing her head in concrete – charges denied by the businessman who was already in custody on suspicion of a number of rapes and the murder of another nightclub hostess when first questioned about Ms Blackman's disappearance.
Speaking to reporters before flying out to Japan's capital city, Mr Blackman said he did not know what to expect from the trial.
"It's a complicated situation and a complicated trial. I'm apprehensive about it because there is an awful lot of circumstantial evidence and he has denied all of the allegations," he said.
However Mr Blackman, who has spent thousands of pounds in air travel to and from Japan in the past seven years, said the end of the trial would also end a "parallel life" for him and his family.
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