This week, Japanese Prime Minister Shinzo Abe made a historic visit to Pearl Harbor in the American state of Hawaii.

　　Abe went there on Tuesday with President Barack Obama.

　　The two leaders placed great importance on the idea of reconciliation. Obama said: "Wars can end, the most bitter of adversaries can become the strongest of allies."

　　The prime minister offered sympathy for the Americans who died in the Japanese attack on Pearl Harbor 75 years-ago. He expressed "sincere and everlasting condolences" for the deaths of more than 2,400 American servicemen.

　　Abe joined Obama in placing wreaths at the U.S.S. Arizona Memorial. The memorial is built over the wreckage of the battleship that was destroyed in the attack on December 7, 1941. The visit brought added attention to the modern-day alliance between two nations that fought each other fiercely in World War II.

　　In his speech at Pearl Harbor, Abe called the relationship between Japan and the United States, "an alliance of hope." Obama called the alliance the cornerstone of the Asia-Pacific area and a force bringing progress around the world.

　　This was not the first visit to Pearl Harbor by a Japanese Prime minister. However, it was marked with symbolism, coming 75 years after the surprise attack that led to U.S. involvement in World War II.

　　It also comes seven months after Obama became the first U.S. president to visit the Japanese city of Hiroshima, where the U.S. dropped the first atomic bomb used in war.

　　A historic visit timed to current politics

　　Jeffery Hornung is a researcher with the Sasakawa Peace Foundation in Washington, D.C. He says the visit has historical importance. But it also shows the depth of the alliance. Japanese-American ties were an issue during the 2016 U.S. presidential election campaign.

　　"It sends a symbolic message to, not only the incoming president-elect, but also to the region, that the U.S.-Japan alliance is stronger than ever, that we are able to confront past problems between us and still be stronger as allies."

　　Abe did not offer an apology for the Pearl Harbor attack. But he is the first Japanese leader to visit the U.S.S. Arizona Memorial.

　　China, Asia's largest economy, criticized Abe's trip to Pearl Harbor. Before the visit, China's foreign ministry said Japan cannot turn over a new page of history without reaching an understanding with its Asian neighbors.

　　China called Abe's effort "wishful thinking."

　　Japanese officials have been concerned that U.S. President-elect Donald Trump may not value the alliance with Japan as other presidents have.

　　U.S.-Japan economic ties remain very deep. However, the inability to pass the Trans-Pacific Partnership trade agreement has hurt Abe at home, says Hornung.

　　"The failure of the TPP even under the Obama administration has been concerning because Prime Minister Abe put a lot of political capital into this. He had to confront some agricultural cooperatives within his own country and really confront opposition with his own party with this to really push it through his country."

　　The Japanese leader noted in his speech the part the U.S. played in rebuilding Japan after the war into the economically strong democracy it is today.