What present to give to a colleague / teacher?

[CarolineDentalTechnician]

Hello,

I'm currently in Osaka on education. It's a 4 weeks course for dental technicians.
We are 5 foreigners in a class with 16 japanese students. They are all very friendly and welcoming.
Our 4 teachers help us wherever they can even if they have a lot of other things to do. The manager of the school did reserve our hostel, showed us supermarkets and restaurants and does everything so we have a good time here.
My question is what we could give before we leave. What is traditional? What is a no go?

Thanks in advance.
Best regards, Caroline