A team of Japanese sociologist and psychiatrists have come up with the best chat-up line in the world.

The line "Rainen no kono hi mo issho ni waratteiy-oh" means literally: "This time next year, let's be laughing together."

The Japanese team - including Takaaki Ishibashi, host of Japan's equivalent to Blind Date - was asked to find the best conversation ice-breaker. The panel said that using "this time next year" sent a signal that the bloke on the pull is interested in more than a one-night fling. "Together" gives the impression of freshness in the romance and "laughing" softens the phrase to make it easy to deliver.

The winning chat-up line is supposed to work anywhere, but particularly well with an office acquaintance. Officials hope it will help solve a population crisis in Japan, where birth rates have plunged.