Japanese wartime song

[Erno]

Sorry if this is the wrong forum, but I've been looking for information on the song played in an episode of the BBC program 'World at War,' and I can't find the title. It's played while women are shown working in fields and rice paddies. Here's a link that should start at the point in which the song is being played:

The World At War Ep22 Japan - Video Dailymotion

Thanks very much in advance for any help you can give in identifying this piece of music!