Alot has already been noted on China's positive and friendly response, more than phone calls, china sent to Japan personnel to help with the disaster in the same way that Japan had sent personnel (JSDF) to China to help during their earthquake in the West. (http://www.eastasiaforum.org/2011/04/15/opportunity-in-crisis-sino-japanese-relations-after-the-earthquake/)
Korea has also been sympathetic. But the Korea defense establish has taken the opportunity to press forward its claims on the takeshima/dokdo islands. see,
http://www.asahi.com/politics/update/0413/TKY201104120653.html?ref=rss
http://www.asahi.com/politics/
http://rss.asahi.com/click.