Here is outline of Procedures for Application for Japanese Entry Visas (PDF).
Those who need to apply for a Japanese visa are requested to contact the Japan Embassy in their home country. The Organizing Committee of iPRES2017 can issue the Letter of Reason for Invitation, Letter of Guarantee and other necessary documents for the convenience of visa applicants.
Please send your request to ipres2017_contact cias.kyoto-u.ac.jp.