By Chris Hogg
BBC News, Tokyo
Is this a climb-down by the Japanese or a clever tactic to try to appease their critics?
Japan has agreed not to hunt humpbacks for the time being
Last month, when Japan's whaling fleet set sail from Shimonoseki, officials announced that as part of their quota of more than 1,000 whales they would try to catch some humpbacks.
Environmentalists were outraged.
Humpback whales, they pointed out, live in close-knit groups. The death of just one could have a significant impact on others.
The species had been protected since the mid-1960s by international agreements but Japan argued that it could hunt humpback whales, just as it could hunt any other species of whale, for scientific purposes.
In any case, its officials said, stocks had recovered from the lows suffered in the latter years of the 20th century.
Now, just a few weeks later, Japan has announced what appears to be a change of heart.
The decision not to hunt humpbacks is the result, it says, of a request by the chairman of the International Whaling Commission, who visited Tokyo a couple of weeks ago.
He asked the Japanese for their co-operation in sorting out the differences between the pro- and anti-whaling nations on the IWC.
The process would take one to two years he said and in the meantime he requested that no humpback whales be killed.
But it is not that simple. Everything changed when Australia elected a new government which promised to pressure the Japanese on whaling.
It announced it would lodge a formal protest against the Japanese whaling mission.
Japan has faced international criticism for its whaling activities
Here in Tokyo, diplomats from the US, the UK, Canada and New Zealand indicated they were ready to take part.
If that did not work, the Australians said they would send a special envoy to lobby the Japanese government on the whaling issue.
In the past officials from Japan's foreign ministry complained privately that a small but vocal minority in parliament and in the fishing industry were tarnishing the country's image abroad, by insisting on the right to continue whaling in the face of international condemnation.
Now their worst fears were confirmed.
Japan's close relationship with the Australians had been "taken for granted" for years.
Everything was different now. A government in Australia keen to prove to its voters it could make a difference was employing new tactics requiring a different approach.
No doubt there were debates and discussions behind closed doors between diplomats, the prime minister's office and fisheries officials.
A decision was reached. The announcement was made - a "postponement", officials stressed, of plans to hunt humpbacks. But that is just semantics really.
Safe for now
This winter the humpbacks will be safe. Next winter they probably will too.
The really interesting question is what happens next.
At the ministry of foreign affairs, they say they are not in a position to reveal on or off the record what the Japanese policy will be from here.
Officially the position is that the scientific whaling will continue. The whalers will not turn back.
Japanese officials say that whaling will continue
But there is no reason for the anti-whaling nations to back down. The pressure they have applied so far has produced results.
They have won the first skirmish, but the battle is not over. Japan's whaling fleet is still in the Antarctic, still hunting.
So if that pressure continues, how will that affect the decision makers in Tokyo?
Will it strengthen the diplomats' hand against the bureaucrats of the fisheries agency?
Or will it strengthen those who say that even when Japan makes gestures to try to respond to international public opinion nothing changes, no one listens, so the country's critics should just be ignored?
Remember, there is still nobody in public life here prepared to stand up and show the Japanese people the uncomfortable truth that across the world in Western nations people are opposed to what is being done to whales in their name.