As 40 Indian soldiers descend on a mock village in the Oahu mountains to hunt for insurgents, they are watched by US Army officers looking for lessons they can apply when leading their units through the same exercise.
The troops are on the island for the biggest joint drills the Indian and US armies have had to date, the latest sign of growing military relations between the two nuclear powers.
The bilateral exercise, called Yudh Abhyas, or "training for war" in Hindi, started four years ago with a handful of Indian and US soldiers. It has since ballooned to feature hundreds of troops, including 140 Indians who flew to Hawaii, which hosts the U.S. Pacific Command whose reach extends to their homeland.
"It's a tremendous expansion," said Col. Dinesh Singh, of the Indian army's 3rd Battalion, 9th Gurkha Rifles. He added the exercises were now teaching platoons from the two nations how to talk to each other in the field.
"If you're talking about interoperability, this is the basic thing. We should be able to understand each other's actions," he said.
After the Sept. 11 terrorist attacks, the US cultivated India as a partner in the war against terror.
Analysts say the US is eager to deepen military ties with India to learn some of the counterinsurgency methods India's military has developed during in Kashmir.
The Americans also want India's large navy to help patrol the seas for terrorists and pirates, analysts say.