TOKYO -- On July 3, when Japanese Prime Minister Shinzo Abe announced that his government would ease some of its sanctions against North Korea, Chinese President Xi Jinping was visiting South Korea for talks with President Park Geun-hye. Xi thus became the first Chinese leader to visit South Korea before going to North Korea.

Xi's trip symbolized a cooling of relations between China and North Korea more than it signaled deepening ties between China and South Korea.

North Korea's Kim Jong Un responded to the trip by firing missiles into the sea.

According to South Korea's Yonhap News Agency, North Korea fired two short-range ballistic missiles on Wednesday. The tantrum of sorts followed missile launches on June 29 and July 2, before the Xi-Park summit.

North Korea watchers say the two missiles fired June 29 were aimed at unsettling Japan before the Tokyo-Pyongyang negotiations. But the missiles only had a range of 500km and could not reach the Japanese archipelago.

So it is fair to say that the missiles, whose short range were enough to get them across North Korea's borders, were meant as a warning to Xi not to visit South Korea.

As it plays its game of missile-launch diplomacy, North Korea also continues to signal South Korea that it would like to sit down for talks. On June 30, it made a "special proposal" for the countries to stop the "slander" and military hostilities between them. On Monday, North Korea said it will send a cheering squad, with athletes, to the Asian Games to be held in the South Korean city of Incheon in September to create a mood for improving bilateral relations and achieving the unity of Korean people.

The launches and special proposals show a Kim who is desperate to end his country's isolation.

North Korea has been subjected to international sanctions since a nuclear test in 2006. The country has been able to avoid economic collapse only because of expanded trade with China.

Trade with China has grown to account for more than 60% of North Korea's total value of external trade. But the friendship between North Korea and China ended with the death of former North Korea leader Kim Jong Il and the establishment of the Xi administration in China.

Frustrated by North Korea's refusal to cancel a nuclear test, Beijing has turned down Pyongyang's repeated requests for a Kim visit to China, according to sources. Not only that, but the Xi administration approached Park's government for the talks, not the other way around.

Now Kim is squirming as he tries to reduce his country's reliance on China.

U.S. cool reaction

Kim has also grown jittery due to the stalemate between North Korea and the U.S. North Korea's basic diplomatic focus is to get the U.S. government to guarantee North Korea's existence by concluding a nonaggression treaty. A concurrent focus is to maintain friendly ties with China.

But the U.S. administration of President Barack Obama has been so preoccupied with the chaos in the Middle East and Ukraine that it refuses to hold talks with North Korea without favorable developments over Pyongyang's nuclear development program.

Kim suggested this spring that his government was preparing for another nuclear test. Then, on June 30, the Korean Central News Agency reported that Pyongyang was preparing to prosecute two detained American tourists. But the U.S. administration has remained hesitant to respond to North Korea's provocations.

Chances are high that North Korea is sounding out South Korea about mutual dialogue in a bid to break the impasse in relations with the U.S. North Korea agreed with Japan on establishing a special committee to investigate the fate of Japanese nationals abducted by North Korean agents in a possible attempt to stimulate South Korea's sense of direct involvement in matters related to its northern neighbor.

Pyongyang repeatedly changes its diplomatic approaches to Japan and South Korea as it struggles to move its relations with the U.S. forward. Japan has lifted some of its sanctions against North Korea in appreciation of Pyongyang's moves on the abduction front but is keeping in place an export ban and the prohibition against the Mangyongbong-92, a North Korean a ferry and cargo vessel, from entering Japanese ports.

The Japanese government needs to carefully consider when to play its bargaining chips vis-a-vis North Korea while closely analyzing relations between the country and its neighbors.