The Lae National Court sentenced Hanson Yatzat after he admitted to stabbing Moses David in the chest on 3 March 2017, which resulted in his death.
The incident took place at the Madang block in Poaba in Lae between 6 and 7pm.
Yatzat was at a black market that evening when the deceased, who was under the influence of alcohol, approached him, hugged him and asked for a cigarette.
Annoyed with him, he pushed the deceased away after he asked for a cigarette.