A teenager who stabbed a 15-year-old boy with a "terrifying" hunting-style knife has been found guilty of murder.
Elton Gashaj sustained "catastrophic" injuries when he was attacked with the 19cm blade in Salt Hill Park, Slough.
Reading Crown Court heard he was stabbed after a fight escalated into "serious violence".
The defendant, also 15, who cannot be named due to his age, denied murder and claimed he was acting in self-defence. He will be sentenced at a later date.
Jurors heard Elton was stabbed with the 19cm-long blade on 21 September last year.
Members of the public had seen a group playing about with pampas grass stalks in the park, before a fight began between Elton and the accused.
Pavlos Panayi QC, prosecuting, told the court: "The fight quickly escalated into serious violence and the defendant produced that big knife and stabbed Elton three times in the upper body.
"Twice in the left hand side of the chest and once in the back."
The defendant had claimed Elton stabbed him first and he had acted in self-defence because he feared for his own life.
The accused, who suffered injuries to his chest and back that medics deemed "superficial", said he had been carrying the knife because he had previously been attacked.
He pleaded guilty to possessing a bladed article.