By Chris Hogg
BBC News, Tokyo
Six Japanese whaling ships have set sail for their annual hunt in the south Atlantic.
Japan says that hunting whales is its sovereign right
Japan's fisheries agency says the fleet has a target of 850 minke whales and 10 fin whales.
Environmentalists have condemned the hunt in the southern ocean whale sanctuary, which will last for several months.
Japan hunts whales every year, and is strongly opposed to a ban on commercial whaling imposed two decades ago.
It says it hunts whales so that its scientists can measure the size of the populations and their feeding and breeding habits.
The meat from the catch is sold and the proceeds used to pay for the research programme.
But environmentalists reject the idea that this is a scientific study. They say politicians and bureaucrats allow the hunt because of intense lobbying by a small but vocal minority.
They quote opinion polls suggesting that the majority of Japanese people rarely or never eat whale meat and do not support whaling in the southern ocean.
The reality is that many Japanese you talk to do not understand what all the fuss is about.
Japan says the fleet will try to catch several hundred minke whales, which are quite small. The stocks, it says, are relatively plentiful.
It will also try to kill 10 fin whales, which are larger and rarer.
The catches are authorised by the International Whaling Commission.
Japan has reason to be bolder this year. At last year's IWC meeting, it persuaded a majority of other nations to make a symbolic show of support for an eventual lifting of the ban on commercial whaling.
And last month another of its allies, Iceland, decided to resume commercial whaling for the first time in seven years.