It started in 1999 with a playful little teapot with a red whistle at the spout.

Some critics wondered if good design would be appreciated by the masses. The teakettle, designed by postmodern architect Michael Graves for Target, didn't immediately fly off the shelves. But it soon became a hot seller, along with other items such as a toilet-bowl brush and a chess set, and the concept of design partnerships took off.

Now Target is celebrating the 20th anniversary of that first collaboration by reissuing iconic pieces from 20 previous partnerships, including Graves, Missoni and Lilly Pulitzer as well as Philippe Starck, Isaac Mizrahi, Anna Sui and Jason Wu.

Others retailers have copied the idea to varying degrees of success. But two decades later, the high-low design collaboration remains one of the hallmarks of Minneapolis-based Target and has cemented its reputation as a purveyor of cheap-chic goods.

Target has done more than 175 collaborations — some big multiyear ones, others small and for a limited time — since first linking up with Graves.

Some have been so popular that they crashed its website. Remember Missoni in 2011 or Lilly Pulitzer in 2015?

Others have had a more tepid reception, ending up on the clearance rack, but still made headlines. Think the partnership with Neiman Marcus that flopped back in 2012.

The anniversary collection, which will hit stores and its website on Sept. 14, will include nearly 300 items priced from $7 to $160, with most items under $50.

The company won't reveal the actual pieces that will be part of the collection for another couple of weeks, to build anticipation. But, reflecting Target's increased focus on inclusivity, the retailer did say the women's clothing pieces will be sold in plus-sizes even if the original partnerships did not come in extended sizes.

Target also has commissioned a book and documentary about its 20 years of democratizing design that will be released this fall.

While these design collaborations were an important ingredient in Target's ascent 20 years ago when they were still more of a novelty, executives and experts alike say they continue to be just as critical, if not more so, to Target today.

"They're these periodic 'wow' moments that are so true to the brand," said Target CEO Brian Cornell. "The reaction it leads to from the guest — they love those moments. It's a reminder we bring this element of style that's accessible and affordable to guests across the country."

While they're not a big enough piece of Target's overall business to make or break a quarter, he said they help drive awareness of Target, send traffic to its stores and its website, and keep the brand on trend.

Back in 1999 when Target first partnered with Graves, the chain was still adding hundreds of stores and expanding to other parts of the country. It was a $21 billion retailer with 851 stores in 41 states. Its main competitors were Kmart, which was then known for its blue-light specials, and Walmart, which was all about everyday low prices.

The design collaborations helped further distinguish Target from that pack at that time, said Wendy Liebmann, CEO of WSL Strategic Retail.

"They elevated what a big-box mass retailer was all about," she said. "It wasn't only about low prices. It was this notion that even if you are potentially lower income you were worthy of good design. That was a very big statement and a differentiating position for a popular-priced retailer to take in those days."

Today, Target has matured, its growth has slowed and it is opening far fewer stores. It is a $75 billion company with 1,853 stores in all 50 states. But the competition has grown more fierce with more retailers selling many of the same items — and not just in stores, but also online, led by Amazon, said Liebmann.

"We see in our research how shoppers are willing to buy anything anywhere," she said. "Today, differentiation and expecting more is more important than ever before."

The seeds of Target's first design partnership with Graves were planted, curiously enough, during the restoration of the Washington Monument in the late 1990s.

Target, which had contributed $6 million to the project, asked Graves to design the scaffolding. Graves was 64 years old at the time, a renowned architect and designer who lived in Princeton, N.J., but who had little name recognition outside of certain circles.

A Target executive had told Graves, "We've been knocking you off for years," Graves told the New York Times at the time. "So why not go right to the source?"

That young Target executive, a vice president in home decor, was Ron Johnson, who went on to have a high-profile career as head of Apple's retail stores and a short-lived stint as CEO of J.C. Penney.

The idea of such a partnership wasn't completely new. Kmart had already linked up with Martha Stewart on a line of sheets and towels. But the difference was that Target knew that Graves was a not a celebrity many people would know.

"We don't think we really need to sell Michael as much as we need to sell good design," Johnson told the Star Tribune in 1999, adding that Target's "soon-to-be-affluent" and educated customers would know good design when they saw it.

Graves' initial collection of 150 kitchenware items was so successful that it was soon expanded to more than 500 items. It went on to be one of Target's longest-running design partnerships, sunsetting in 2013, two years before Graves died.

It was followed by other collaborations with designers such as Philippe Starck, who re-imagined baby products; Todd Oldham, who tackled dorm accessories; and Isaac Mizrahi, who offered womenswear.

In later years, Target managed to use up-and-coming designers such as Proenza Schouler, Jason Wu and Joseph Altuzarra before they hit the big time as well as more well-known brands such as Hunter.

These days, most of Target's partnerships tend to be for a limited time. The more popular ones, such as Missoni and Lilly Pulitzer, can lead to such frenzies that stores are mostly sold out within hours. Some items in its most recent collection with Vineyard Vines sold out online within a day.

Over the years, some customers have alleged that Target purposefully keeps inventory low to lead to quick sellouts in order to get more buzz out of them. When that happens, the items often show up soon after on eBay for three to four times the price.

But Target officials have responded that the collections are meant to last weeks and that it's hard to predict demand.

Now that Target in the past few years has refreshed its portfolio of private-label brands, such as its blockbuster kids' clothing line Cat & Jack, the design partnerships also have the added benefit of bringing more attention to its other new in-house brands, said Carol Spieckerman, a retail consultant.

"The overall effect is to freshen up the floor and take away some of the predictability that was beginning to plague Target," she said.

In the meantime, other retailers have pulled off their own celebrated design collaborations. H&M has linked up with the likes of Alexander Wang, Karl Lagerfeld and Versace. Kohl's sells a lower-priced Vera Wang line.

"Other retailers have jumped into the design partnership fray, but Target is still most known for it," Spieckerman said.

Kavita Kumar • 612-673-4113