One of the big set pieces of Rim of the Pacific war games — a Marine Corps amphibious assault within the fictitious island nation of Griffon — came from many directions Saturday at Kaneohe Bay, and with help from partner nations in the region.

F/A-18 fighter attack jets screamed over Pyramid Rock Beach providing mock close-air support, with assistance from Cobra attack helicopters.

Japanese reconnaissance soldiers landed on the beach in black rubber rafts. CH-53E Super Stallion helicopters and tilt-rotor Ospreys simulated bringing in troops.

Hundreds of Hawaii Marines and Japanese soldiers arrived from the sea in three waves of amphibious assault vehicles.

Two of the U.S. Navy’s most capable amphibious ships, the USS America and USS San Diego, were parked just offshore, while Australia’s biggest navy ship, the HMAS Canberra, operated off Bellows, putting Australian, New Zealand, U.S. and Tongan forces ashore with its watercraft.

Brig. Gen. Ray Descheneaux, commander of Fleet Marine Forces in RIMPAC 2016, said the full spectrum of amphibious operations was built into the scenario, which is occurring during the four-day “free play” phase of the exercise. The final phase started Friday and is more reactionary and less scripted.

“We want to have that humanitarian assistance piece, we want to have that forcible entrance from the sea,” Descheneaux said. “We want to have that over-the-horizon capability exercise. Because any one — or all — of those elements could come into an issue or event here in the Pacific.”

Growing staple

Although amphibious operations have been a Marine Corps staple for decades, it is the new must-have capability for a growing number of friendly and partner nations in the Pacific. And in this RIMPAC, increased interoperability is a focus.

“It’s important to drive home the point that the U.S. isn’t going to do this (amphibious mission in the real world) alone,” Descheneaux said. “We are going to operate with our combined and coalition partners.” It’s something the Navy has repeatedly stated — it can’t go it alone in the region.

The U.S. amphibious force is “flexible, scalable and is rapidly responsive,” the Center for Strategic and International Studies said in a June report. “As a result, the amphibious force is frequently called on during the initial phase of a crisis response.”

Japan and Australia are working to establish standing amphibious capability, according to CSIS. South Korea is expanding its ship capacity, and India, the Philippines and Singapore want stronger amphibious forces.

Amphibious operations today include providing humanitarian assistance as well as a combat capability, but the goal is the same: getting forces inland from the sea without relying on established infrastructure.

Teamwork, tactics

In the scenario, Griffon, a nation supported by coalition forces, is at odds with the nation of Orion. During peace talks, Orion sank a Griffon ship to try to make Griffon pull out of the talks.

Also in play is a fictitious terrorist organization, Disputant Resistant Armed Combatant Opposition or DRACO, which has kidnapped a journalist and soldiers.

DRACO forces occupied parts of a simulated airfield at Kaneohe Bay, and Saturday’s amphibious landing secured the area for follow-on forces. Another part of the scenario took place Friday with a long-range raid on the Pacific Missile Range Facility on Kauai.

Cpl. Grant Barron, 20, an Echo Company Marine with the 2nd Battalion, 3rd Marines who took part in the Kaneohe Bay beach assault, said it was the biggest exercise he’s been a part of in his 2-1/2 years in the Marine Corps.

“It takes a lot more communication, a lot more teamwork up and down the chain of command,” Barron said. “You can’t just expect everyone to know what they are doing right off the bat.”

Echo Company worked alongside Japanese soldiers, and other Hawaii Marines trained with South Koreans and Australians during earlier parts of RIMPAC, he said.

“We got to work with the Japanese. We got to shoot their weapons. They got to shoot our weapons,” Barron said. “We got to kind of see their tactics versus ours.”

Also during RIMPAC, Navy hovercraft and Marine Corps amphibious assault vehicles operated from the Australian Canberra’s rear well deck, while Australia’s assault boats entered and exited the USS San Diego’s well deck. Marine Corps Ospreys, Super Stallion helicopters and Navy MH-60 Sea Hawk helicopters conducted their first landings on the Canberra.

The ships are slated to pull back into port Tuesday and Wednesday for the close of RIMPAC 2016.