North Korea is poised to conduct a fourth nuclear test and continues to develop ballistic missiles to carry its nuclear warheads. It also continues to rattle sabers against the South. So why is Tokyo contemplating a deal that will lift some sanctions on the North in return for information on abducted Japanese?

The timing is strange because the North is more isolated than ever. Seoul and Washington remain steadfast that Pyongyang should make the first move toward denuclearization before talks can resume. Even Beijing is putting...