A young boy who was one of the youngest in the country to gain his black karate belt had it stolen when his dad's van was broken into, near Doncaster.
The belt was in a sport bag in his dad's van, which was parked on Baulk Lane, Harworth, on Sunday.
The belt is embroidered with Toby Carter in gold writing.
His dad's black belt, embroidered with Leon Carter, was also in the bag.
Toby's mum, Jane Carter, said: "These were presented on the night they passed their grading and at nine years old, Toby was one of the youngest in the country to pass at this level so this belt is of enormous sentimental value to him and us as a family.
"Both belts are of absolutely no use to anyone else so I'm hoping the bag was dumped somewhere and we can get them back, so if you could keep your eyes peeled whilst out walking we would be ever so grateful."