From 1 September, the Working Holiday agreement between the governments of Iceland and Japan will take effect.
Japanese citizens interested in applying for a Working Holiday based residence permit must fulfil all the basic requirements for a residence permit in Iceland as well as the age criteria. The purpose of stay shall be to experience the culture and general way of life in Iceland and the permit is granted for a maximum of 12 months. A permit holder receives an unlimited work permit and may work in Iceland and change his/her job without applying at the Directorate of Labor for the duration of the stay.
More information here