In the case you plan to establish Japanese language school in Japan, you need to satisfy several requirements.
1 Principal ( assumed you ) needs to have experience of engaging in teaching Japanese language for five years or more.
2 The number of teachers is three or more ( including you ) and at least one teacher for 20 students
3 All teachers should have graduated from university in faculty of teaching Japanese language
They should have studied teaching Japanese language in university
4 They have passed 日本語教育能力検定試験
Moreover, facility ( building and land of school ) should be owned by operator of school.
In the case of lease right, valid period of lease contract is 20 years or more.
Room area of building should be more than 115 square meters or more.