What is the fine-grained topic of the following text: When the rail was completed by end of 1943 and the Japanese began to regroup all the POWs from Thailand and Burma at one of the large camps or hospitals in Thailand, many 2/4th of S Battalion ended up at Tamuang Camp where they were deemed ‘fit’ by the Japanese and selected to work in Japan. Only return the topic.
Japanese regrouping of POWs during WWII at Tamuang Camp for labor in Japan