The draining of the marshes for rice cultivation drew Burman migration into British Burma even before the final annexation of Upper Burma. The Bamar however were virtually excluded from military service, and even as late as 1939 there were only 432 Burmans in the army compared with 1448 Karens, 886 Chins and 881 Kachins. Karen villagers had acted as guides for the British during the Anglo-Burmese Wars, and Karen troops had played a major part in the suppression of rebellions in Lower Burma in 1886 and again in the "Saya San" rebellion of 1930-32.