President Joe Biden and Prime Minister Fumio Kishida unveiled the biggest ever upgrade in US-Japan defense ties Wednesday during a lavish White House state visit aimed at countering a rising China.

Biden was rolling out the red carpet for Kishida with a luxurious dinner, plus music by legendary US singer Paul Simon, as he sought to underscore the importance of Japan as a crucial ally in the Asia-Pacific region against Beijing.

"This is the most significant upgrade in our alliance since it was first established," Biden told a press conference with Kishida in the White House Rose Garden.

The US president, 81, said their relations were "unbreakable" and that their agreements on Wednesday set a "new benchmark for our military cooperation." 

The two leaders unveiled plans to restructure the US military command in Japan, the biggest such change since the 1960s -- while the United States, Japan and Australia would also launch a joint air defense network.

The move is aimed at making US and Japanese forces more nimble in the event of a crisis such as a Chinese invasion of Taiwan.

'Purely defensive'

The upgrade comes amid tensions about Beijing's claims over both Taiwan and huge swathes of the South China Sea, despite efforts by Washington to reduce the risk of conflict.

Biden insisted that the military upgrade in China's backyard alliance was "purely defensive" and "not aimed at any one nation or a threat to the region."

Kishida meanwhile called during the press conference for "peace and stability" across the Taiwan Straits.

But Biden has made no bones about his desire to create alliances across the region to counter China.

On Thursday, he will host the first trilateral summit between Japan, the Philippines and the United States, aiming to deepen their alliances.

The pomp-filled state visit for Kishida was however also meant to underscore the broader cultural and economic relations between two allied nations who were at war 80 years ago. 

Biden announced that a Japanese person will be the first non-American to walk on the Moon, flying on a US mission due to take place in a few years' time.

The leaders also announced deals for technology, including artificial intelligence and the economy.

'Democracy over autocracy'

The rest of Wednesday will be dedicated to extravagant hosting of 66-year-old Kishida and his wife Yuko.

The state dinner will be held in the grand East Room of the White House, decorated by fans and cherry blossom branches.

White House chefs will serve a meal featuring Japanese flavors, starting with house-cured salmon, followed by dry-aged rib eye with wasabi sauce, and salted caramel pistachio cake with cherry ice cream.

After dinner, Paul Simon "will perform a selection of his iconic songs," White House Social Secretary Carlos Elizondo told reporters.

First Lady Jill Biden said during a preview of the dinner that it would celebrate the "flourishing" US-Japan friendship. 

"Our nations are partners in a world where we choose creation over destruction, peace over bloodshed, and democracy over autocracy," she said.

Kishida is the first Japanese leader to get a US state visit since Shinzo Abe in 2015, and only the fifth world leader to receive one since Biden took office in 2021.

Staunchly pacifist for decades, Japan has in recent years made "some of the most significant, momentous changes" since World War II, US ambassador to Japan Rahm Emanuel said ahead of the visit.