By Chris Hogg
BBC News, Tokyo
Tough talk from Tokyo has been the immediate response to North Korea's missile launch.
But what happens next?
The Japanese are working in tandem with the Americans to try put together a plan that will show the international community is speaking with one voice.
That work started minutes after the first launch was confirmed.
The launch reminds Japan it lives under the threat from Pyongyang
The US ambassador to Japan, Thomas Schieffer, arrived at the Japanese prime minister's offices at first light on Wednesday morning for consultations with Japanese ministers.
But no matter how close are the relations between Tokyo and Washington, it will not be easy to get their response right.
Japanese public opinion demands a strong response. The launches of the missiles have reminded people that they live under the threat of military action by Pyongyang.
It does not matter that the missiles tested this time did not reach Japanese soil. Missiles tested in the past have flown over Japan.
Today the threat feels a lot more real than it did yesterday for many here.
What is more, the missile launches make the list of grievances the Japanese public have about North Koreans a little longer.
Other issues which Tokyo feels are unresolved include the abduction of Japanese nationals to train North Korean spies and allegations that Pyongyang launders money and exports narcotics to Japan.
So there are elements in Japanese society that are urging firm action from their politicians, including economic sanctions.
But one of the frustrations the Americans face is that no matter how close their relationship with the Japanese, Tokyo's troubled ties with China and South Korea can make it difficult to come up with a common position across the region.
For instance, during the six-party talks aimed at trying to resolve the North Korean nuclear issue, there have been disagreements among the participants about whether or not Japan should raise the abduction issue.
Getting agreement on sanctions from nations more friendly towards North Korea - like China and Russia - might become difficult.
The focus of diplomatic efforts for now is of course the United Nations Security Council.
Japan is expected to circulate a draft resolution condemning North Korea.
It will be the first time in three years that the Security Council will have held detailed discussions on North Korea.
China and Russia face a tough decision. North Korea fired the missiles in the face of repeated calls from the international community not to do so.
So where do their best interests now lie - in punishing North Korean leader Kim Jong-il, or protecting him in the hope this will increase the influence they have over him?
Analysts say it is hard to work out with any degree of certainty what lay behind this test.
Some argue it was an attempt by North Korea to remind the Americans - who have shifted the focus of their non-proliferation efforts away from North Korea to Iran - that the issue still requires their attention.
Others say the United States' efforts to clamp down on alleged money-laundering by the North Koreans through banks and businesses based in the southern Chinese enclave of Macau are biting hard.
There is less money to pay the North Korean army, so it is harder for civilians within the government to resist the hard line some elements in the military want to pursue.
Others still argue that this is an attempt by some in the military to head off efforts by some in the government to embrace the market reforms seen in China.
They fear that if these are pursued, North Korea might end up little more than a client state of Beijing.
These are educated guesses at best. When pressing the foreign ministry in Tokyo for their evaluation of what lies behind these latest tests, they say: "Ask Pyongyang."
It is tempting to argue that nothing has changed, the missiles did not hit Japan, the new intercontinental ballistic missile the North Koreans have built came down less than a minute after it was fired.
But on the other hand, everything has changed. The missile tests were carried out in defiance of international opinion.
The international community now has to come up with an appropriate response. It will not be easy.