"I was mentoring a young man last year who was nine years old and wearing a stab proof vest to go to the barber's shop - you can see what we're up against," said Shelim Ali.
He heads up Knives Down Guards Up, which offers self-defence, karate skills and mentoring to help keep young people in Bristol safe from knife crime.
Ali started his sessions in a space under the M32 motorway in 2023 following a spate of stabbings in the city.
"If I can save one life I'm happy, if I can save 100 and have my arms around the city, I'm blessed, but I just believe we need to get the word out," said the former karate teacher.
Ali, 47, and from the Knowle area of the city, has been teaching karate, delivering seminars and participating in competitions for almost 30 years.
After he began the Knives Down Guards Up sessions under the M32, numbers grew until about 60 kids were turning up.
He held his first indoor session at the St Paul's Community Centre on Saturday.
The classes are aimed at providing young people with the skills to recognise and respond to peer pressure and conflict.
Ali has been nominated as a champion for the Everyone Active leisure centre chain, which means he can use their facilities for free.
"It's the first time we're taking our seminars from outside in the cold and the rain and bringing it indoors, so we're trying to ramp up the community to back it," he said.
"I truly believe that as coaches, mentors and parents, we need to inspire young people - that there are choices they can make."
Amy Hanson, who brought her six-year-old daughter Juelz to Saturday's session, said: "I just want them to learn some self-defence, the world they're growing up in at the moment is absolutely terrible.
"I just want them to be able to look after themselves and feel safe really, for my peace of mind."
On Ali, she said: "My children went to his karate class and they absolutely love it. I think they need someone like him, he's a very good role model."
Klarissa Reddicks, who took her 11-year-old daughter Mashyah along, said: "I think it's very important for me as a mother, in the world today, that I arm my daughter with the appropriate skills to defend herself and to look for danger.
"Firstly she'll use her words, which is her strongest weapon, and then, heaven forbid, if there is a worst-case scenario, she can do what's necessary to keep herself safe."
Lloyd Russell, community ambassador for Empire Fighting Chance, and long-time mentor of Ali, said: "Social media has got a hold on young people."
He praised Ali for sticking to the task of providing positive advice and guidance to young people, adding: "We can only keep on doing what we're doing."
The issue of youth violence has been highlighted in a new documentary called Postcodes, which focuses on the historical tensions between Hartcliffe and Knowle West in the south of the city.
The film explores the ways that some young people deal with losing a friend to knife crime and reveals children as young as 10 are carrying weapons.
Zak Dugdale, a youth worker who works in both Hartcliffe and Knowle West, was involved in setting up the 224 Youth Zone, a new £12m youth centre located between the two areas.
He described Knives Down Guards Up as "one of many great projects" in Bristol, adding: "We need more of it, really."
After 20 years of cuts to youth services, he said the new youth zone that opens in June was "a big step in the right direction" but more needs to be done.
In the meantime, he said collaboration between different initiatives was important.
"I think there's a lot of great work going on all across Bristol and we're seeing more partnerships working together to support what young people are telling us," he added.
A Bristol City Council spokesperson said the authority's bid £1m bid to be named one of eight areas to introduce a Young Futures Hub model was successful.
This will see new support for young people aged 10-18, extending up to 25 for those with special educational needs and disabilities (SEND), to boost their access to activities and opportunities, including support for skills and career development.
The next Knives Down, Guards Up seminar is due to take place in June.