A schoolboy died after being kicked "like a football", a court heard.
The court heard Deividas was armed with a plastic pipe
Deividas Strizegauskas, 13, died of a brain haemorrhage the day after he was attacked in a brawl in east London, the Old Bailey heard.
Deividas, from Plaistow in east London, had gone with friends to confront boys from another school in Prince's Terrace, near West Ham's ground.
Seven youths, three aged 15 and four aged 16, deny murder and an alternative count of manslaughter.
Deividas was armed with a plastic pipe component from a vacuum cleaner, the court heard.
Sir Allan Green QC, prosecuting, said a teacher who tried to stop trouble from breaking out had seen Deividas with something up his sleeve, but he claimed he was only going to use it "for my protection".
One of the alleged murderers, 14 at the time, was the next day "telling the whole class that he had stamped on Deividas's head" but later told police he had only said this "out of bravado".
Other boys told police they had not been involved or were acting in self-defence.
One of the boys said he had seen that "about 15 youths were kicking Deividas like a football".
The trial was later adjourned until Friday.