The Tokyo District Court has found American musician Richard Hinds guilty of murdering the Irish student Nicola Furlong.
Hinds, 19, was sentenced to five to ten years in jail with labour. In Japan, 10 years is the maximum jail term for a juvenile who is under the age of 20.
The prosecutors argued that maximum punishment was appropriate in this case.
The incident took place in May last year when 21-year- old Furlong was found strangled in the Keio Plaza Hotel in Tokyo. Hinds denied committing the murder but admitted he had put "light pressure" on the victim's neck.
The defence pleaded that a combination of a prescription drug and alcohol found in Furlong's bloodstream could have led to her death.
The judge said Hinds showed "no remorse" for his actions and had "tainted the honour of the victim".
Describing the incident as "atrocious and vicious", the panel of judges said that the convict "violated the dignity" of the victim when he tried to portray her as "promiscuous."
Furlong, originally from Curracloe, County Wexford, was in Japan as part of her studies.
"I am so angry and I am so hurt, we had so much faith in the Japanese doing justice for us and I don't feel we got it, I am disgusted," said the Irish student's sister Andrea Furlong, after the verdict.
Only a week ago, Hinds's friend was also convicted for sexually assaulting Furlong on the same night she died.
"We hope it's more than five and up to ten. If he is good in jail he will be out in five, it is only two years more than the other fella," said the victim's father, Andrew Furlong, referring to Hinds's friend.