Old mobile phones will be used to make the Olympic and Paralympic medals for the Tokyo 2020 Games.
The Japanese public will be asked to donate old phones and small appliances to gather two tonnes of gold, silver and bronze for the 5000 medals.
The project hopes to promote sustainability and reduce costs.
To collect the phones boxes will be placed in local offices and telecoms stores from April and will remain there until the metal required has been collected.
Olympic host cities have traditionally obtained the metal from mining firms. However, Japan, which does not have many mineral resources, is keen to take the theme of a sustainable future a step further.