June 7, 2012: Japan revealed that it would place some of its Aegis destroyers, equipped with anti-missile missiles, closer to North Korea if North Korea seemed ready to test another long range missile. This will be the second time Japan deploys these ships near North Korea.
The first time was last April, and along with the warships Japan also deployed warplanes under the "self-defense" provision of their pacifist constitution. Adopted, under pressure from the United States after World War II, Article 95 (of the Self-Defense Forces Law) allows Japanese military forces to deploy warships and warplanes to defend each other. And that is what Japan did last April to possibly shoot down North Korea's planned "satellite launch" (which was seen as a violation of a recent North Korea agreement to halt its nuclear weapons and ballistic missile program). Japanese F-15s flew out to protect the Japanese Aegis destroyers. The Aegis ships carry missiles capable of intercepting ballistic missiles, or low orbit satellites. The Aegis radar system can locate and track these targets.
Japanese deployed three Aegis equipped destroyers for this mission, two in the East China Sea (south of South Korea) and one in the Sea of Japan (off the west coast of Japan). The F-15s are prepared to fire warning shots, or shoot down, aircraft trying to interfere with the Japanese destroyers.
To help with this effort the United States towed its SBX (Sea Based X Band radar) to the area. SBX is a large long range radar built on a floating platform that can be towed to wherever it is needed. The X-Band radar can see over the horizon and gives anti-missile systems that maximum warning time that a target is on the way.
The North Korean rocket failed shortly after launch, falling into the sea off the coast of South Korea. The North Korean rocket failed before the Japanese had a chance to fire any of their anti-missile missiles. The North Koreans are preparing another long range ballistic missile for launch and the Japanese are ready to shoot it down.