Why did the allies capture so few japanese soldiers when they attacked iwo jima

I believe the answer is: The Japanese had planned for no surviving prisoners

Compared to the allies army, the japanese soldiers were notoriously known for bearing high honours in sacrificing their life for their country.

This make their commanders tend to make plan to abandon all prisoners and many of the cornered Japanese soldiers still choose to fight and shoot despite being cornered. This make capturing japanese soldiers become a really huge burden for the allies forces.

byzantine empire is the answer i think you are looking for.

hope this : )

d. migration of french settlers into english colonies