I am now certain.
That I will waste some 300K away.
I initially thought that I'd rather err on the side of caution; that even when I don't know if I wanted to go to japan, I'd rather not be a helpless tourist there. Hence the language course.
Only after I paid the down payment, 300K, I notice that i will most likely waste the money away. the course is in 3 hours a week, for 12 weeks. and I'll be gone by half of the course.
But I have had history of burning money on courses I don't attend anyway, so it won't be something new. Sadly.