Let the marathon begin.

For many Black Friday shoppers, the race to scoop up the best deals will begin well before they even digest their turkey.

An unprecedented number of retailers have scheduled early openings on Thanksgiving Day — for the first time Toys R Us will open at 9 p.m., Wal-Mart at 10 p.m. and Best Buy, Macy’s and Target at midnight — to get a jump start on holiday sales.

"It’s always a pivotal point of the year," said Shawn Troup, Best Buy’s Iwilei store manager. "It’s the biggest sales day of the year by far. If you do well on ‘Green Friday,’ it sets you up for a successful season. If you don’t do well, then it puts you in a hole that’s difficult to dig yourself out of."

Black Friday — traditionally one of the busiest shopping days of the holiday season — got its name because sales on that day can push retailers in the black for the whole year. By some estimates, holiday sales account for as much as 40 percent of a retailer’s annual business.

But the ubiquitous day-after-Thanksgiving sales that traditionally started at dawn on Friday have slowly moved earlier and earlier until they now cut into Thanksgiving dinner.

Retailers say they have to open earlier to compete with 24/7 online operations like Amazon.com that promote deep discounts the entire week.

"For local off-line retailers to lengthen their Black Friday opening time is kind of a way to deal with that," said Qimei Chen, professor of marketing at the University of Hawaii’s Shidler College of Business. "The more time consumers spend in the store, the more likely they will spend more money. Competition is just really formidable."

As many as 152 million U.S. consumers plan to shop this year on Black Friday weekend, up from the 138 million people who planned to do so last year, according to the National Retail Federation. The organization projects a modest 2.8 percent year-over-year growth in sales to $465.6 billion, which is reflective of the state of the economy.

Retail sales in Hawaii have slowly recovered since the economic slump that began in late 2007. Hawaii retail sales were strong in the first half of 2008, totaling $25.5 billion, according to Retail Merchants of Hawaii. But by 2009, sales had fallen to $23.5 billion and inched up in 2010 to $24.3 billion.

From January through July this year, Hawaii’s retail industry posted year-over-year increases in sales — between 5.2 percent and 25 percent — each month. Sales through July totaled $16.2 billion.

"We’re probably on track to do better" than last year, said Carol Pregill, president of Retail Merchants of Hawaii. "We’re anticipating a good holiday season. As stores become more competitive, the reasons to buy becomes more urgent."

Sales at Pearlridge Center have been "slowly creeping up" from January through July by 1 percent to 4 percent each month, but were flat for most of the fall, according to general manager Fred Paine.

"The news was all bad and people were just a little more conservative," he said. "People are just nervous. People are just generally spending less money. Everything’s doom and gloom that you read about. Prices are going up all the time for everybody. Gas is expensive. It’s not a real cheery outlook on the global front."

Still, Paine is hoping a "pent up" buying splurge will translate into a 6 percent to 7 percent year-over-year boost in sales this holiday season, compared to last year’s 8 percent to 9 percent, coming off weak recessionary years.

Ala Moana Center is anticipating a "very successful season" based on strong year-to-date sales coupled with new stores including the state’s first Bath & Body Works and Diane Von Furstenberg, according to group marketing manager Scott Creel.

Ala Moana retailer Martin & MacArthur expects sales in excess of 20 percent over last year due in part to its strategy to diversify with a personal line of koa watches, koa sunglasses and koa Tungsten rings, said Michael Tam, president and CEO.

"The competitive environment among specialty retailers is more intense than ever before," Tam said. "The fierceness of the competitive environment with specialty retailers is showing up all across Hawaii as well as across the country in that you see retailers discounting and dropping prices on commodity goods even earlier and faster and deeper. Customers are much more weary and they’re less likely to spend money impulsively. You’ve got to maneuver smartly in this environment because the same old things aren’t going to work anymore."

As retailers plan earlier openings this year, consumers are lining up days in advance as well.

Hoona Utu, 36, and his 16-year-old son, Ruston, started camping out at the Aiea Best Buy at 7 p.m. Monday to snatch up a 42-inch LCD TV for $199, instead of the normal price of $500 to $600.

"Since our generation now is headed to electronics, that’s the whole reason I’m here. You got cellphones, portable computers, laptops, kids games. It’s just crazy, but that’s the direction where the future’s headed," Utu said. "With the prices they have it’s worth the wait plus I get to spend time with my son."

However, early openings aren’t welcome by all, particularly employees forced to cut short Thanksgiving meals to prepare for the crowds.

Employees at Best Buy and Target have created online petitions at Change.org, urging the big-box giants to push back their original opening time to 5 a.m. on Black Friday. The Target petition, by a North Omaha store employee, has received nearly 200,000 signatures.

A midnight opening "robs the hourly and in-store salary workers of time off with their families on Thanksgiving Day," the petition said. "All Americans should be able to break bread with loved ones and get a good night’s rest on Thanksgiving."

Avid discount shopper Renee Tulonghari agrees that stores have taken it too far.

"I wouldn’t want to change my family traditions to save an extra dollar," she said. "It’s kind of ‘Scroogish’ to open; it’s all about the dollar bill. I bet next year more stores will open and Thanksgiving will turn into a retail holiday. Now that’s bah humbug."