THE giant Mahakam River is the highway into the interior of East Kalimantan. Oceangoing ships can travel as far as Samarinda, 60 kilometers upstream from its mouth on the coast, to load huge logs floated down to this port. Beyond Samarinda, the river is slow, broad and muddy with shipyards, sawmills, villages and coconut groves dotting its banks.

The lower half of the river valley is populated by Muslim Malay groups, including the native Kutai. Da