Now 13, but 12 at the time of the alleged offence, he is accused of raping a 12-year-old girl after school in a sandpit.
The boy sat at a long table next to his parents in the youth court at Newport, Isle of Wight, as the girl wept while giving evidence from another room on a video link.
The boy is the youngest to be tried since a change in the law last September allowed children under 14 to be charged with the offence.
The girl said she had not known the boy well when she went out to play and met him after school. The accused asked her to go to a field and play. They sat near the edge of a sandpit and talked. Then, she said, the boy told her: 'I'm going to have sex with you.' He pulled her trousers down and put his penis inside her. It hurt and it seemed a long time before he got off. Then, she said, he got on his bike and rode off.
In an interview with the police she was asked why she had gone to the field with him. She said: 'I try to make friends with people and I trust people, or I used to anyway.'
She denied taking the boy's penis out and undoing his trousers, or telling the other boy later that she would kill the accused if she was pregnant.
Mr Price suggested that what happened had been with her agreement. In tears, the girl said: 'No.'
Dr Hester Clarke, a police surgeon, said her medical examination was consistent with recent sexual intercourse.
The hearing continues today.Reuse content