On April 25, DPJ President Banri Kaieda released the following statement.

Yesterday, a leadership summit was held between Japanese Prime Minister Shinzo Abe and United States President Barack H. Obama, and a Japan-U.S.
Joint Statement was announced today. Along with my appreciation for President Obama's visit to Japan, I would also like to express my basic approval for the fact that Japan and the United States have produced a Joint Statement in order to indicate the road to be taken toward deepening our Alliance.

This statement has achieved certain important results with regard to national security, such as confirming in the high-level format of a joint statement that commitments under the Japan-U.S. security treaty also include the Senkaku Islands. At the same time, I take note that the Joint Statement pays attention to the importance of building constructive relations with neighbouring nations, by for example stating "both countries reaffirm their interest in building a productive and constructive relationship with China".
I value this statement.

However, the Japan-U.S. Alliance cannot shape the future of the Asian-Pacific through Joint Statements alone. Future actions by President Obama and Prime Minister Abe will be key. In particular, we strongly urge Prime Minister Abe not just to work to strengthen deterrence, but to develop a balanced Asian diplomacy, including regarding the issue of historical perception.

With regard to the Trans-Pacific Partnership treaty (TPP), it is our perception that the gap between Japan and the United States was not narrowed by this leadership summit. The government should honour Diet resolutions and take a stance that protects those items which ought to be protected, such as the five key agricultural products, as well as attacking in areas where they should take the initiative, such as automobiles. Furthermore, despite the fact that the Japanese people have a keen interest in the TPP, neither the public nor the Diet has been able to obtain any information regarding it. This robs the Japanese people of their right to know and is unacceptable. We strongly urge the government and ruling parties to implement thorough information disclosure, including through enacting the "Bill for promoting the disclosure of information regarding TPP negotiations", submitted to the Diet today in a DPJ-initiated effort.