Kishida appeared leery of China's apparent willingness to intercede with North Korea, a development Kerry is hailing as a potential way out of the standoff. Japan wants to make sure its disputes with China over navigation and land rights in the South China Sea are not pushed aside, and Kishida took care to outline the Japanese position again Sunday.
North Korea has readied midrange missiles for a probable test launch meant to show that it can attack U.S. allies and bases. The missiles have a range of about 2,500 miles, putting South Korea, Japan and U.S. bases in those nations and on Guam at risk.
North Korea regularly ignores U.N. Security Council prohibitions on such missile launches and nuclear tests, and it has reneged on disarmament pledges from past negotiations.
Pyongyang recently said it would restart a nuclear reactor whose closure was the only lasting accomplishment from fitful international bargaining that included the United States.
Those talks, which included direct U.S.-North Korean discussions on the sidelines, fell apart nearly four years ago. Another effort failed in the 1990s.
Kerry said he is stepping carefully, with an eye to past failures.
"We spent years in the same dynamic, so it's fair to try to require some indicator of good faith that the dynamic is going to be different," Kerry told reporters.
He added: "I'm open personally to exploring other avenues," maybe through China. "I'm not going to be so stuck in the mud that an opportunity to actually get something done is flagrantly wasted."