The US-Japan alliance benefits both sides. And Shinzo Abe has claimed that the aim of his visit to the US is to reaffirm this solid alliance and display close relations between the US and Japan. However, the alliance is faced with some tricky problems that cannot be resolved through simple talks.

First, the summit cannot ease up the dispute over the Diaoyu Islands. It is not a simple territorial row, but a complex problem related to the systematic reconstruction in the Asia-Pacific region after the Cold War. But concerning the Asia-Pacific dynamics, the US and Japan have different ideas.

Second, Japan will not enter into the TPP which is a significant blow to the US.

US efforts to proactively push the Asia-Pacific region toward economic integration are focused on the TPP negotiations and particularly Japan's attitude toward them.

Obama pays close attention to the TPP and hopes Japan can take concrete action to join in.

However, participating countries will not only make broad cuts to tariffs on goods, but also will tackle regulatory barriers and liberalize services such as banking or insurance. These three conditions, if fully accepted, may seriously undermine the capability of the Japanese government.

Although some politicians from the ruling Liberal Democratic Party claim that Japan can enter into the TPP conditionally, it is still impossible for Japan to satisfy the US.

Third, the US will not support Japan's desire to amend its Peace Constitution as it views the move as a challenge.

The US joined in the construction of the international order after World War II. It will not allow Japan to change the constitution which was originally drawn up by the US.

Both Japan and the US clearly understand each other's bottom line. These tricky issues might be touched during the summit, but will not really affect the talks between the two leaders.

This article was compiled by Global Times reporter Zhao Nan, based on an interview with Liu Junhong, director of the Center for Globalization Studies of the China Institutes of Contemporary International Relations. zhaonan@globaltimes.com.cn