Shikata ga nai

is a Japanese phrase and cultural concept. The phrase means "it cannot be helped" or "nothing can be done about it". "Shikata ga nai" implies a kind of hard work which is defined by Japanese culture.
If something happens which is beyond someone's ability to control or affect, a conventional Japanese reaction is to say "shikata ga nai". With this phrase, someone recognizes that a problem exists and then gets on with doing what can be done. 
Shoganai.
The phrase is another way to say that it's useless to try to do something.
After the 2011 Tōhoku earthquake and tsunami, "shoganai" was one of the most commonly heard expressions.