I think, it is Ganbaru (頑張る) not Kanbaru , also romanized as gambaru, is a ubiquitous Japanese word which roughly means to slog on tenaciously through tough times.
The word Ganbaru is often translated to mean "doing one’s best", but in practice, it means doing more than one's best. The word emphasizes "working with perseverance" or "toughing it out."
Ganbaru means "to commit oneself fully to a task and to bring that task to an end."
It can be translated to mean persistence, tenacity, doggedness and hard work. The term has a unique importance in Japanese culture.