Visa requirements for Japan
Japan has Non Visa Required status.
You don't need a transit visa to travel through Ireland.
You can stay in Ireland without a visa, for touristic reasons or to take a short course, for up to 3 months.
You need an immigration permission to stay in Ireland for more than 3 months.
You will need an immigration permission to work in Ireland.
You can get a study visa if you enrol on a full-time recognised course. You will have a limited permission to work during the course of your study. The exact details of the permission to stay and your entitlements to work will depend on the course you are taking.
In general you are entitled to work 20 hours per week during school term and 40 hours per week during holidays.