LONDON (Adage.com) -- Japanese clothes retailer Uniqlo has found a novel way of encouraging U.K. shoppers give the brand a big presence on Twitter -- by reducing the price of clothing pieces every time someone sends a tweet about an item.

The "Lucky Counter" promotion has been running ahead of the relaunch of Uniqlo's U.K. e-commerce site this week, and has seen the brand's name appear in Twitter's trending topics list for the country.

In a web page dedicated to "Lucky Counter," users can choose from 10 pieces they would like to see discounted on the website when it relaunches on September 9.

Clicking on one of the pieces of clothing brings up a pre-written tweet using the hashtag #luckycounter. Users can add their own message and then send it, and watch the price fall.

The more tweets users send about a particular item, the lower the price goes. At the time of writing, one of the items -- a gray, crewneck long-sleeve T-shirt -- had hit its target price of nearly 60% off, meaning it will go on sale on Thursday at $4.60 instead of $10.70.

Uniqlo worked with Hiroki Nakamura, web director of its global advertising agency, Dentsu Japan, to create the campaign. The U.K. is the first market that Uniqlo, which also has stores in the US, France and throughout Asia, has tried the approach.

The company has relied solely on users to spread the word on Facebook and Twitter, rather than paying for promotional tweets, as well as trailing the promotion heavily on its website, which was otherwise closed for business.

The tweets being sent are largely a mixture of people taking part in the promotion and those who are telling their followers about Uniqlo's unusual social-media experiment.

Amy Howarth, head of marketing at Uniqlo in the U.K., said: "The initial aim was to maintain contact with the customer while the website was temporarily closed for its e-commerce migration.

"The campaign has been really successful and we've been delighted with the response to date. Customers seem to really want to engage with us, and it's great as the campaign is so transparent and immediately dynamic, so they can see their tweets actually making a difference."

After the new site goes live, Uniqlo will promote it with an online pinball game called "Lucky Machine," offering a cash prize and discount codes.

Uniqlo has frequently used Twitter in its marketing campaigns. This year's efforts have included Utweet, which delivered users a personalised video based on tweets that they had sent to promote the UT T-shirt line; and Sportweet, which also drew on users' tweets combined with footage of athletes to promote Uniqlo's sportswear.

With all its Twitter activity, Uniqlo%u2019s U.K. Twitter account has fewer than 5,000 followers.

Uniqlo and another of its agencies, Tokyo-based IMG SRC, won an award for the "Lucky Switch" campaign, which used a widget to embed Uniqlo images on other blogs and websites at the click of a button. It won the Grande Innova Lotus at Asian award ceremony AdFest.