Upvote:-3
According to Rome2Rio the cheapest flight between Ukraine and Japan is 270β¬ single, from Boryspil (kbp) to ChΓΌbu Centrair (ngo).
To find these flights you'll have to search regularly as prices can change every minute.
If you're under 26 you may be able to find youth tickets, which you can't find using normal flight search engines but only at the carriers own websites.