An alleged gangster has admitted to shooting the mayor of Nagasaki last April in a killing that shocked Japan.
Mr Shiroo is said to be linked to the Yamaguchi-gumi crime group
Tetsuya Shiroo, 60, shot Itcho Ito near an election campaign office in the city on 17 April.
On the first day of his trial, Mr Shiroo told the Nagasaki court: "I apologise to Mayor Itcho Ito and his family from the bottom of my heart."
The main issue in the trial is expected to be whether or not Mr Shiroo intended to kill Mr Ito.
Japan's Kyodo news agency reported that defence lawyers were arguing that the killing was not premeditated.
But prosecutors say Mr Shiroo harboured a grudge against Mr Ito from February last year, when the mayor expressed his intention to seek a fourth term in office.
Mr Shiroo told the court that everything in the indictment was true, adding: "Every day, I pray that Mr Ito rests in peace."
Mr Shiroo is thought to be linked to one of Japan's leading criminal groups, the Yamaguchi-gumi.
The attack shocked people in Japan - a nation that sees little gun crime and where handguns are strictly banned.
At the time, incumbent Prime Minister Shinzo Abe described the shooting as unforgivable.
The trial of Mr Shiroo is expected to last until mid-March.