The Kobayashi Maru is a training exercise in the Star Trek franchise designed to test the character of Starfleet Academy cadets in a no-win scenario. The Kobayashi Maru test was first depicted in the 1982 film Star Trek II: The Wrath of Khan, and it has since been referred to and depicted in numerous other Star Trek media.
The notional goal of the exercise is to rescue the civilian spaceship Kobayashi Maru, which is damaged and stranded in dangerous territory. The cadet being evaluated must decide whether to attempt to rescue the Kobayashi Maru—endangering their ship and crew—or leave the Kobayashi Maru to certain destruction. If the cadet chooses to attempt a rescue, an insurmountable enemy force attacks their vessel. By reprogramming the test itself, James T. Kirk became the only cadet to defeat the Kobayashi Maru.
The phrase "Kobayashi Maru" has entered the popular lexicon as a reference to a no-win scenario. The term is also sometimes used to invoke Kirk's decision to "change the conditions of the test."