If you were a Nazi prisoner at war, you were faced with a 4% chance of not surviving the war.
Japanese Soldiers in the Battle Fields During World War 2

By comparison the death rate for allied powers held by the Japanese was nearly 30%.

The Japanese armys victories in second world war was largely a result of the poorly equipped soldiers extreme sacrifice. In the imperial army, surrender was not an option - they fought to the last man standing.

Japanese nationalism meant that the military was built around a concept of the time period: a Rich Country has a Strong Military. Nationalists asserted that Japan as a land was sacred, and its people were special due to a combination of Zen-Chan and various forms of Japanese Buddhism with Shinto. Service in the Japanese military was seen as service to the Emperor. Each soldier in theory believed it was a great honor to die for the Emperor as the samurai concept "to serve" was deeply ingrained in all the soldiers culture

The training did not only consist of physical abilities, but also spriritual traning, named "Seishin Kyoiku" which means Mental strength. It put enthasis on duty, obideince, courage and self sacrifice. They had a book called "Senjinkun" in which they had a certain sentence, that every Japanese Soldier knew:

"Duty is heavier than a mountain, death i lighter than a feather."

In the Japanese culture, surrender was shameful, if not to say unthinkable. The only reason as to why, the Japanese soldiers had such a succesfull time at war, was due to their extreme commitment and warrior sprit, because eventhough they didnt have the weapons and other war assets, which the opponents had, they had the courage and drive, which lead them to small victories.