Last year, the mood was muted and many cherry celebrations were cancelled after the March 11 earthquake and tsunami which killed nearly 19,000 people. The disaster also set off a nuclear crisis.

At Tokyo's Ueno Park, where 1,200 cherry trees make it one of the capital's most popular cherry-viewing spots, signs were erected encouraging visitors to show "self-restraint" out of respect. The threat of power cuts also dampened spirits.

But this year, thousands are kicking back under the blossoming trees and raising a glass to the future - the often raucous get-togethers involve plentiful beer and sake.

"During last year's cherry blossom season we were in a mood of self restraint after the earthquake," said Yui Nakayama, 24, who with her party of 15 colleagues was waiting for another 50 people to join them on Thursday night.

"Japan has become energetic again, so I'm happy to relax and enjoy myself with my colleagues today."

The parties called "hanami," or "flower viewing" in Japanese, are spring traditions held among families, friends and co-workers. Parties beneath the cherry trees can go on all day and night, especially on weekends.

Cold weather has meant the blooms in Tokyo opened some five days later than usual, and the festive mood has been enhanced by relief that the trees suffered little damage after the country was hit on Tuesday by typhoon-force winds that snarled transport and left several people dead.

Not even the impending launch of a satellite by North Korea sometime over the next week or so, which Tokyo suspects may cross into Japanese territory, could dent the revelry.

"I'm concerned about the rocket launch, but it would be unproductive to stay indoors just for that reason," said Miki Sugai, who was picnicking with her 3-year-old son and two other mothers.

"I'm trying to refresh myself by fully enjoying this cherry blossom season."

(Reporting by Reuters TV, writing by Ruairidh Villar, editing by Elaine Lies)

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