It is unlikely that the Japanese welcomed the hearing as the Embassy and MOFA are yet to get clear guidance as to how to pursue the issue. Thus, they are in their usual delay and deny mode. Japan's new Justice Minister Chiba appears to have indicated a that she will push to have Japan sign the Hague Convention and to change child custody laws. But with so much else going on, this issue might be getting lost in the fray.
It is equally unlikely that the U.S. State Department welcomed the hearing. Assistant Secretary of State Kurt Campbell, by the way, was not scheduled to testify. It was to be someone from the Bureau of Consular Affairs who works on children's issues. The hearing would have highlighted but another intractable, unpleasant issue the U.S. has with Japan. A summit with lots of expectations and no deliverables, it not desirable.
At his "town meeting" with the left-behind parents and grandparents, Campbell made a point of saying that there seems to be some progress on the subject with Japan. And he preferred to wait and see what will happen. However, he assured the families that if nothing materialized in the next few months, the U.S. would rethink its strategy. One mother's sobs were audible.