Mauritian citizens are not required to obtain visas to enter Japan for temporary visits less than 90 days for the purpose of tourism, commerce, conferences, visiting relatives / acquaintances.
For cases involving paid activities or staying more than 90 days, a visa is required.
You can find more information regarding Exemption of Visa on the following web site:
Web Site of MOFA

For the moment, the Embassy of Japan in Mauritius cannot accept visa application.
For further information, the applicant should address to the Embassy of Japan in Madagascar:
Web Site of the Embassy of Japan in Madagascar
To apply for a visa, please read carefully the instructions below:
Web Site of MOFA