With a history of struggling to survive against larger, stronger countries, North and South Korea are remarkably similar in how they view neighbors China and Japan -- with wariness and lingering bitterness.

"Koreans have had to maintain their independence against stronger, more aggressive neighbors," who they regard with an element of suspicion, explained Gary Samore, director of studies at the Council on Foreign Relations.

In particular, he said, memories of Japan's 35 year-long occupation of the Korean Peninsula in the first half of the 20th century still provoke feelings of dislike and even hatred.

"Japanese colonialism and occupation of the peninsula was a difficult and bitter pill to swallow," explained Evans Revere, president of the Korea Society. The Japanese compelled Koreans to change their names and speak Japanese in an effort to integrate the population.

More recent events have stoked tensions with Japan, especially a visit made by Japanese officials and lawmakers to the Yasukuni Shrine, a controversial memorial in Tokyo dedicated to those who fought for the Emperor of Japan and containing what many consider to be a revisionist version of World War II.

Many Koreans believe Japan has not fully owned up to its actions in World War II, said Jack Pritchard, president of the Korea Economic Institute.

Critics assert governmental oversight of history textbooks in Japanese schools, which must be authorized by the Ministry of Education, has sanitized negative aspects of Japanese activities before and during the war.

Nonetheless, in the past several years, relations between Japan and South Korea seemed to make progress, and may continue to improve under the current Japanese government, Revere said.

But while South Koreans are establishing a working relationship with Japan, North Korea has virtually no relationship with Japan at all, said Samore.

North Korea abducted more than a dozen Japanese citizens in the 1970s and '80s, ostensibly to teach Japanese language and culture to North Korean spies. The North's leader, Kim Jong Il, admitted to the kidnappings, which took place under his father's reign as leader, and returned five survivors, but the issue continues to fan anger between the two nations.

And in some ways, North Korea has an interest in maintaining an antagonistic relationship with Japan as a means of justifying some of its military and political activities, added Revere.

A general feeling of distrust exists toward China as well, according to Samore. South Korea is worried the Chinese are strategically trying to create a strong presence in North Korea in case it collapses. And North Korea is working to become less dependent on China because it believes the communist power is pursuing its own interests, he said.

Though troubles erupt between the nations, the Koreas and China had a relatively cordial relationship for hundreds of years, explained Revere. Much of the Korean language is derived from Chinese, and the traditional Chinese teachings known as Confucianism have had a major cultural influence.

But "Koreans, and North Korea in particular, are nothing if not nationalistic," and border disputes and Chinese occupation of the Korean Peninsula have not helped matters, he said.

The ideological tie between China and North Korea as communist nations only took them so far, and when China began moving to a more open and decentralized economic state, the North's bitterness grew.

As for South Korea, its relationship with China has blossomed since China supported the South's entry into the United Nations in the early 1990s, leading to significant economic and cultural exchanges, said Pritchard.

Koreans have been setting up businesses and factories in China to take advantage of the lower labor costs, he said.

According to Samore, however, the honeymoon period of South Korea embracing China's trade opportunities and influence on North Korea has worn off, and now South Korea is nervous about Chinese efforts to build its economy.

Even with their long and complicated pasts, and uneasy present, the four nations participate in six-party talks with the United States and Russia over regional issues, such as eliminating the North's nuclear weapons program in exchange for aid, and are working to bridge the political gulf that has existed for decades.

-- By Larisa Epatko, Online NewsHour