Cobra Gold, one of the largest multinational military exercises in the world, begins its 29th year of joint training by six Asia-Pacific theater countries Feb. 1 in Thailand.

Exercises in the Pacific are seen as an important form of military diplomacy as U.S. Pacific Command at Camp Smith keeps watch over an area with five of the world's largest armies.

Hawai'i is central to much of that training in terms of planning and troop participation, but those efforts often get more notice overseas than they do here.

Participation in Cobra Gold will cost U.S. Army Pacific at Fort Shafter about $20 million, according to the command. But the multinational exercises pay back big dividends in terms of relationships and military interoperability, U.S. officials say.

Defense Secretary Robert Gates recently spoke about the importance of training with India, a growing economic and military power.

"One of the great successes in recent years," Gates said, "has been the increase in the number and complexity of joint training exercises between our militaries — exercises that not only increase trust and confidence, but also prepare our armed forces to confront security challenges that can only be solved by many nations working in concert."

The deployment of 17 Hawai'i-based Stryker armored vehicles to India for the exercise Yudh Abhyas 09 in October represented the largest deployment of Strykers outside of Iraq and Afghanistan.

One of the big exercises that gets visibility in Hawai'i — because it's held in Hawai'i — is Rim of the Pacific, or Rimpac, held every two years. The 2010 dates haven't been announced. In 2008 it was held from June 29 to July 31.

One of the world's largest maritime exercises, Rimpac two years ago brought together military forces from Australia, Canada, Chile, Japan, Netherlands, Peru, South Korea, Singapore, the United Kingdom and the U.S.

Participating were 35 ships, six submarines, 150 aircraft, and 20,000 sailors, airmen, Marines, soldiers and Coast Guard personnel.

Four target ships were sunk in the war games off Kaua'i: the destroyers Fletcher, David R. Ray and Cushing, and the cruiser Horne. Marine Corps Training Area-Bellows is used for amphibious landings by tracked and air-cushioned landing craft.

The Navy four years ago estimated that Rimpac had a $43 million economic impact on Hawai'i.

About 14,000 military members from Thailand, the U.S., Singapore, Indonesia, Japan and South Korea will take part in Cobra Gold in Thailand.

"Thailand is one of our closest friends and partners in Asia, as well as being our oldest ally in Asia," said Lt. Gen. Benjamin R. Mixon, commander of U.S. Army Pacific.