Oswald Wynd The Forty Days.

Wynd's World War 2 novel is set in the Fall of 1943 aboard a Japanese merchant ship (the fictitious OSHIMA MARU) as it transports 1200 Allied prisoners of war from Singapore to Japan by way of Saigon. The novel sticks closely to Japanese POW transport fact as revealed after the war, with the prisoners crammed into the ship's two cargo holds and only allowed out on deck at rare intervals. Wynd's plot initially revolves around two British prisoners (a Territorial Army major put in charge of "his" cargo hold and a Japanese-speaking Englishman who serves as interpreter between the major and his Japanese captors) and two Japanese (the ship's civilian captain and the Japanese Army major in charge of the prisoners' transport), but soon focuses on the British interpreter and the Japanese Army commander. The author is surprisingly sympathetic towards his Japanese characters and even seems to try and understand why the Japanese major commits, at the novel's climax, a horrific war crime (he beheads an American merchant seaman whom he believed was about to start a prisoner mutiny). This is certainly not the sort of work that could have been written during the war or even in the 1950s. Japanese-speaking Wynd's attitudes are made even more curious by the fact that he had been a prisoner of war in the Far East during the war and had, it appears, even been transported from Singapore to Japan aboard a ship similar to the OSHIMA MARU. Some critics reviewed The Forty Days at the time of its publication as a sort of sea-going Bridge Over the River Kwai; most present-day readers will question such an assessment.