Ganbaru

, also romanized as gambaru, is a widely-used Japanese cultural concept. It roughly means to slog on or stick to it through tough times. "Ganbaru" implies a kind of hard work which is defined by Japanese culture.
The word "Ganbaru" is often translated to mean "doing one’s best". In practice, it means doing more than one's best. The word emphasizes working with continued effort despite difficulties, failure, or distraction. The term means "toughing it out".
"Ganbaru" means to commit fully to a task and to bring that task to an end. 
"Ganbaru" means an active process of doing something. It contrasts with a passive process. 
History.
The term "ganbaru" developed from the related concept of "gaman". 
After the 1995 Kobe earthquake, the slogan "Gambaro Kobe" was used to encourage the people of the Kobe region. 
After the 2011 Tōhoku earthquake and tsunami, "ganbaru" was one of the most commonly heard expressions.