I'm trying to write a screenplay about WWII that's hopefully as historically accurate as possible, and one of my main characters is a Japanese soldier sent to Okinawa from the home island. I was wondering whether or not the Japanese military had sent in soldiers as reinforcements even after the fighting there had started.
No Japanese reinforcements reached the island after the battle began, but several formations were sent to Okinawa beginning in mid-1944 as the battlefield began to shift westward toward the Home Islands. Of these the 44th Independent Mixed Brigade, 15th Independent Mixed Regiment, 23d Medium Artillery Regiment, and 100th Independent Heavy Artillery Battalion were all sent to Okinawa directly from Japan, arriving in June, July, October, and July of 1944 respectively. The 44th Independent Mixed Brigade was attacked by American submarines while enroute and all but destroyed; it consisted of the 1st and 2d Infantry Units, the latter of which was rebuilt in the late summer using manpower drawn from Kyushu and Okinawa. The 1st Infantry Unit was not rebuilt; instead it was replaced by the 15th Independent Mixed Regiment.