Education and early intervention is needed to tackle knife crime, according to the Chief Constable of South Wales Police.
In an interview with ITV Wales he said children are carrying knives for kudos.
Anti-knife crime lessons are not compulsory, but several schools across Cardiff have invited the police into class to discuss knife crime. Teachers say knife crime is an issue primary school children of all ages are aware of.
Headteacher of St Mary the Virgin Church in Wales Primary School in Cardiff says it's important that children get the right message at the right time on issues like knife crime.
Police Community Support Officer Laura Moore has been visiting schools in her community to build up rapport with pupils from as young as 4, so the message of prevention can be filtered through as they get older.
A Welsh Government spokesperson said: