I know that Korean laborers were used on many islands (Guadalcanal and Tarawa come to mind immediately as places where I know I’ve read of them) but I’m not sure about Iwo Jima.
I did a quick check of Richard Wheeler’s “Iwo” and found no mention of Korean laborers there. One aspect that makes me doubtful is that the island was so difficult for the Japanese to supply (even water had to be brought in by ship) that any non-combatants would be more a drain than they would be worth for their labor.
A soldier can dig as well as a slave and when he’s finished digging, he’s a trained fighter.
Thanks for your note.
In 1995, during the 50th anniversary of the Iwo invasion, I read an essay about this by a Korean historian.
His essay was translated from a Korean newspaper, but I have no idea where I saw it in the American press.
I have seen brief references to this story a couple times since 1995.
Like you, I was completely surprised at this story.
My Dad actually “fought” at Iwo (Army radar specialist, landed D+3), so our house had a lot of books and magazines about it, and I always thought the Japanese dug the cave system.
As I recall, a substantial number of the 1000 “Japanese” troops who surrendered were in fact Koreans.
As I recall, a substantial number of the “Japanese” soldiers who were shot while trying to surrender were also later determined to be Korean.
As I recall, the Koreans dug some of the primary tunnel system in 1943-44, and they were slowly withdrawn when the Japanese began to staff up in the spring of 1944.