Thomas Pryde beat Adam Alexander over the head with an iron bar during a row and then buried the body in waste ground.
He kept his secret for years, but made a drunken confession to his wife Angela while on holiday in Greece. When the couple later split up, she went to the police. The body has never been found.
Mr Alexander's mother, Tricia Bremner, was in court to hear Pryde's lawyer reveal that the killer had provided more information to try to pinpoint the grave, near Errol, Perthshire.
Pryde, 38, a drainage contractor, of Scone, Perthshire, admitted the culpable homicide of Mr Alexander, 38, at his home in Errol in November 1999, and disposing of the body.
The judge, Lord Bracadale, told Pryde at the High Court in Edinburgh: "You got into an argument and started fighting with him. In the course of that, you hit him repeatedly with an iron bar and killed him. You put his body into your car and drove home to get a shovel. You drove to another place, stripped him and buried him on waste ground.
"To this day, the body has never been found, despite efforts which you have at least made and continue to make to assist in that regard."
Lord Bracadale said he would have imposed a sentence of 14 years, but it could be discounted to ten years because Pryde had pleaded guilty.
Mr Alexander, a long-distance lorry driver, was reported missing when he failed to turn up for work on a Monday morning.
Pryde was known to have been at Mr Alexander's home that weekend to buy a motorcycle, and he provided a witness statement.
In 2006, Pryde went on holiday with his wife and son. He disclosed during a drunken argument that he had killed Mr Alexander. In the following months, the marriage broke down and they separated.
Mrs Pryde went to the police, who learned that Pryde had also confessed to other people over the years but they, too, had kept quiet.
Pryde told detectives: "I just completely lost the plot. He shook me quite aggressively. We ended up fighting. I managed to dodge quite a lot from him. He was a lot stronger than me… we rolled about… a bar or something… I was on the ground and I hit him with it. I put him in the back of the car. I panicked. I took him along by the brickworks and buried him.
"What happened that night will never go away from me. I can always remember the fact that I thought it was him or me."
The advocate-depute, Alex Prentice, QC, said Mr Alexander's mother described him as a loving and caring person. She had said his loss caused her life to "have no substance".
In 2008 Pryde was jailed for five years for firing a shotgun over the house of a man who had not paid him for a job. He is still serving that sentence.